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Worksheets

PHYSICS_JAMB

Total questions: 396

Worksheet time: 5hrs 57mins

Name
Class
Date
1.

In a collision between two objects, kinetic energy is conserved only if

a)

one of the objects was initially at rest.

b)

Potential energy is converted to work.

c)

the collision is inelastic.

d)

the collision is elastic.

2.

The quantity of motion of a body is its

a)

acceleration.

b)

displacement.

c)

momentum.

d)

velocity

3.

The volume of a fixed mass of a gas varies inversely as the pressure on it, provided the temperature is constant. This statement is

a)

Pressure law.

b)

Charles' law.

c)

Boyle's law.

d)

General gas law.

4.

An image formed on a screen is always

a)

inverted.

b)

magnified.

c)

upright.

d)

virtual.

5.

How would the capacitance of a parallel plate capacitor be affected if the distance of separation of its plates is decreased? It will

a)

increase in value.

b)

decrease slightly.

c)

remain unchanged.

d)

drop to zero.

6.

Which of the following machines does not apply the lever principle?

a)

Claw hammer.

b)

Wheelbarrow.

c)

Single pulley.

d)

Sugar tong.

7.

The average distance moved by a molecule between collisions is called

a)

molecular distance

b)

intermolecular distance

c)

mean distance

d)

mean free path

8.

Which of the following waves requires a material medium for its propagation?

a)

Radio waves.

b)

Light waves.

c)

Sound waves.

d)

X-rays.

9.

The depolarizing agent in a Leclanché cell is

a)

carbon rod

b)

ammonium chloride

c)

manganese (IV) oxide

d)

zinc plate

10.

The material used to slow down the neutrons in a nuclear reactor is

a)

boron

b)

copper

c)

graphite

d)

uranium

11.

Which of the following statements explains why hot soapy water is more effective in cleaning oil-stained dishes?

a)

Hot soapy water lowers the surface tension and emulsifies the oil, making it easier to remove.

b)

Hot soapy water is more abrasive than cold water.

c)

Hot soapy water has a higher pH than cold water.

d)

Hot soapy water evaporates faster than cold water.

12.

Select the correct statement.

a)

The oil on the dishes repels the soap

b)

Soap and heat decrease the surface tension of water

c)

Hot water increases the surface tension of oil

d)

Soap increases the surface tension of oil and water.

13.

The diagram above illustrate a beam of parallel rays from a distant object O, incident on one side of total reflecting prism. Which diagram does not represent the correct path of the beam when it emerges from the prism?

a)

A. W

b)

B. X

c)

C. Y

d)

D. Z

14.

An electrical device has 50 turns in its primary coil and 20 turns in the secondary coil. The device can be a/an

a)

step-up transformer

b)

step-down transformer

c)

d.c. generator

d)

a.c. generator

15.

The earpiece of a telephone handset converts energy from ?

a)

electrical to sound

b)

sound to electrical

c)

radio wave to sound

d)

sound to radio wave

16.

Two identical cups containing the same volume of water at 45°C and 5°C, are left in a room at 25°C. Which of the following graphs correctly illustrates variation of temperature with time?

a)

A

b)

B

c)

C

d)

D

17.

A 60 kg man stands on a weighing balance in an elevator. If the elevator accelerates upwards at 5 m/s² determine the reading of the scale. [g = 10m/s²]

a)

900 N

b)

600 N

c)

300 N

d)

1200 N

18.

The length of an iron bar is 100 cm at 20°C. At what temperature will its length increase by 0.01%?

a)

48.0°C

b)

38.0°C

c)

28.3°C

d)

23.0°C

19.

A moving-coil galvanometer which gives a full-scale deflection with 0.005 A is converted to a voltmeter, reading up to 5 V using an external resistance of 975 ohms. What is the resistance of the metre?

a)

0.25 ohms

b)

2.50 ohms

c)

25.00 ohms

d)

250.00 ohms

20.

A beam consisting of alpha-particles, beta-particles and gamma-rays pass through a magnetic field at right angles to the direction of the field. Which of the following observations would be made about the alpha-particles, beta-particles and gamma-rays respectively?

a)

Deflected, deflected, deflected

b)

Deflected, deflected, not deflected

c)

Deflected, not deflected, deflected

d)

Not deflected, deflected, deflected

21.

A parallel plate capacitor is charged and the charging battery subsequently disconnected. If the plates of the capacitor are moved farther apart by means of insulating handles, the

a)

capacitance would increase.

b)

capacitance would decrease.

c)

charge on the capacitor would increase.

d)

charge on the capacitor would decrease.

22.

The velocity of sound in air at 15°C is 340ms⁻¹. Calculate the velocity at 47°C

a)

A. 790ms⁻¹

b)

B. 602ms⁻¹

c)

C. 358ms⁻¹

d)

D. 322ms⁻¹

23.

Which of the current-voltage characteristics shown below is that exhibited by an ohmic conductor?

a)

A

b)

B

c)

C

d)

D

24.

A 500N box rests on a horizontal floor. A constant horizontal force is exerted on the box such that it moves through a distance of 8m. If the co-efficient of kinetic friction between the box and the floor is 0.22. Calculate the work done on the box.

a)

880J

b)

440J

c)

400J

d)

110J

25.

The normal force on the ball is

a)

mgsinθ

b)

mgtanθ

c)

mgcosθ

d)

mgcotθ

26.

The net force on the ball along the plank is

a)

mgsinθ+ F

b)

F - mgcosθ

c)

mgsinθ - F

d)

F+ mgsinθ

27.

What factors determine the frequency of a note emitted by a vibrating string?

a)

Amplitude of vibration, force constant of string and length of string

b)

Amplitude of vibration, force constant and tension in string

c)

Mass per unit length of string, tension in string and length of string

d)

Force constant of string, tension in string and length of string

28.

The magnitude of the force experienced by a charge of 1.6 × 10⁻¹⁹ C in a uniform electric field of intensity 5 × 10⁶ NC⁻¹ is

a)

3.2 × 10⁻¹⁴N

b)

8.0 × 10⁻¹³N

c)

8.0 × 10⁻¹⁰N

d)

3.1 × 10⁻¹³N

29.

Which of the following statements about viscosity is not true?

a)

depends on areas of the surfaces in contact.

b)

occurs in fluids.

c)

is independent of the relative velocity of the layers.

d)

depends on the tangential force between the layers.

30.

A motorcycle starting from rest, is uniformly accelerated such that its velocity in 10 s is 72 kmhr⁻¹. What is its acceleration?

a)

108 ms⁻²

b)

86 ms⁻²

c)

4 ms⁻²

d)

2 ms⁻²

31.

The Temperature of an object is raised by 120ºC. The resulting increase in its absolute temperature is

a)

50K

b)

120K

c)

200K

d)

393K

32.

An electron of mass m and charge e moves in a circular path in a magnetic field of flux density B. How long does it take to complete one orbit?

a)

2me/Bπ

b)

2B/meπ

c)

2πm/Be

d)

Be/2πm

33.

Which of the following statements about photoelectrons is correct?

a)

A. A faint green light produces with less kinetic energy than a bright red light.

b)

B. A red light releases a smaller number of electrons than a green light.

c)

C. A faint green light produces photoelectrons with greater kinetic energy than a bright red light.

d)

D. A red light produces more photoelectrons a green light

34.

The sketched graph above illustrates the heating curve of a 0.02 kg of water. Determine the approximate value of the specific latent heat of vaporization of water.

a)

2.25 × 10⁶Jkg⁻¹

b)

4.17× 10³Jkg⁻¹

c)

2.00 × 10³Jkg⁻¹

d)

1.00 × 10

35.

In the hydraulic press, the force F applied is related to the diameter d of the cylinder by

a)

F∝d²

b)

F∝d

c)

F∝d⁻¹

d)

F∝d⁻²

36.

In an electric circuit, an inductor of inductance 0.5 H and resistance 50Ω is connected to an alternating current source of frequency 60 Hz. Calculate the impedance of the circuit.

a)

50.0Ω

b)

150.5Ω

c)

195.0Ω

d)

1950.1Ω

37.

Which of the following statements correctly explains why a total solar eclipse would be seen by people on only a small portion of the earth surface?

a)

moon is larger in diameter than the earth.

b)

earth is larger in diameter than the sun

c)

earth revolves around the sun.

d)

earth is larger in diameter than the moon.

38.

Water waves have a wavelength of 3.6 cm and speed of 18 cms⁻¹ in deep water. If the waves enter a shallow water with wavelength of 2.0 cm, calculate the speed of the waves in the shallow water.

a)

0.4 cm/s

b)

2.5 cm/s

c)

10.0 cm/s

d)

10.8 cm/s

39.

An a.c generator can be converted to a d.c electric motor by replacing the

a)

slip rings with a split ring and connecting

b)

split ring with slip rings and connecting

c)

a.c with d.c source and connecting a slip rings

d)

a.c with d.c source and connecting split rings

40.

A ray of light obliquely from a less dense medium to a denser medium. Which of the following statements is true about the light?

a)

The wavelength of the light increases in the second medium

b)

The speed of the light increases in the second medium

c)

The light refracts towards the normal.

d)

There is a change in the frequency of the light.

41.

An electron of mass 9.1 x 10⁻³¹ kg is travelling at a speed of 2.0 x 10⁶ m/s. Calculate the associated wavelength of the electron.

a)

3.63 x 10⁻¹⁰ m

b)

3.63 x 10⁻⁸ m

c)

3.63 x 10⁻⁷ m

d)

6.89 x 10⁻⁴ m

42.

Which of the following statements about the process of melting of a solid are true? The temperature of the solid will

a)

II and III only

b)

III and IV only

c)

I, II and III only

d)

II, III and IV only

43.

A diver steps off a diving platform that is 10m above the water. If there is no air resistance during the fall, there will be a decrease in the diver's

a)

gravitational potential energy.

b)

total mechanical energy.

c)

kinetic energy.

d)

momentum.

44.

Which of the following actions would increase the electric force between two positively charged particles?

a)

Decreasing the mass of the particles

b)

Decreasing the distance between the particles

c)

Increasing the distance between the particles

d)

Increasing the mass of the particles

45.

A luminous object is one that

a)

Reflects light

b)

Emits its own light

c)

Absorbs light

d)

Refracts light

46.

A. gives off dim blue-green light only in the dark. B. gives out light of its own. C. shines by reflected light only. D. glows only in the presence of light.

a)

gives off dim blue-green light only in the dark.

b)

gives out light of its own.

c)

shines by reflected light only.

d)

glows only in the presence of light.

47.

Which of the following units is not fundamental?

a)

Metre

b)

Kilogram

c)

Joule

d)

Candela

48.

The vacuum between the double walls of a thermos flask reduces heat loss through

a)

conduction and radiation.

b)

convection and conduction.

c)

radiation only.

d)

conduction only.

49.

In photoelectric effect, the number of electrons emitted per second from a metallic surface is proportional to the

a)

A. intensity of the incident radiation.

b)

B. frequency of the incident radiation.

c)

C. energy of the incident radiation.

d)

D. work function of the metal.

50.

When two cells of negligible internal resistances and equal e.m.f. denoted by E₁ and E₂ are connected in parallel, the combined e.m.f E is given by

a)

E = E₁ + E₂

b)

E = E₁ = E₂

c)

E = (E₁ + E₂)/2

d)

E = 0

51.

1. An elastic material of length 3 m is to be stretched to produce an extension three times its original length. Calculate the force required to produce the extension if the force constant of the material is 982.3 Nm⁻¹. What is the force required to produce the extension? A. 11787.6 N B. 2946.9 N C. 982.3 N D. 8854.7 N

a)

11787.6 N

b)

2946.9 N

c)

982.3 N

d)

8854.7 N

52.

State the function of each of the following parts in a solar panel for heat supply: (a) metal flat plate; (b) thermal insulator; (c) tubes.

a)

(a) Absorbs solar energy; (b) Reduces heat loss; (c) Carries heated fluid.

b)

(a) Reflects sunlight; (b) Increases heat loss; (c) Stores electricity.

c)

(a) Generates electricity; (b) Absorbs heat; (c) Provides structural support.

d)

(a) Cools the panel; (b) Conducts electricity; (c) Filters water.

53.

4. The velocity v of a wave in a stretched string depends on the tension, T, in the spring and the mass per unit length μ of the spring. Which of the following is the correct expression for v in terms of T and μ, using the method of dimensions?

a)

v = √(T/μ)

b)

v = Tμ

c)

v=Tμ2v = \frac{T}{\mu^2}

d)

v = μ/T

54.

5. A satellite launched with velocity Ve just escapes the earth's gravitational attraction. Given that the radius of the earth is R, Ve is equal to:

a)

2gR\sqrt[]{2gR}

b)

gR\sqrt[]{gR}

c)

2gR

d)

g/R\sqrt[]{g/R}

55.

A bullet is fired from a gun at 30° to the horizontal. The bullet remains in flight for 25 s before touching the ground. Calculate the velocity of projection. [g= 10 ms-2]

a)

Velocity of projection = 125 m/s

b)

Velocity of projection = 100 m/s

c)

Velocity of projection = 150 m/s

d)

Velocity of projection = 75 m/s

56.

State three properties of lasers that make them preferable to ordinary light beam.

a)

High intensity, monochromaticity, and coherence

b)

Low intensity, polychromaticity, and incoherence

c)

High intensity, polychromaticity, and incoherence

d)

Low intensity, monochromaticity, and incoherence

57.

A torque is defined as:

a)

The product of force and the perpendicular distance from the axis of rotation

b)

The sum of force and mass

c)

The difference between force and distance

d)

The product of mass and acceleration

58.

Free fall is defined as:

a)

The motion of an object under the influence of gravity only.

b)

The motion of an object in water.

c)

The motion of an object with air resistance.

d)

The motion of an object due to applied force.

59.

A body is thrown vertically upwards from the top of a tower 40.0m high with a velocity of 10.0 m/s. Calculate the time taken for the body to reach the ground.

a)

Time taken = 4 seconds

b)

Time taken = 2 seconds

c)

Time taken = 6 seconds

d)

Time taken = 8 seconds

60.

A cube of wood of side 8.0 cm, floats at the interface between oil and water with 2.0cm of its lower surface below the interface. Given that the relative densities of oil and water are 0.72 and 1.00 respectively, calculate the mass of the wood.

a)

Mass of the wood = 61.44 g

b)

Mass of the wood = 45.12 g

c)

Mass of the wood = 80.00 g

d)

Mass of the wood = 100.00 g

61.

Resonance frequency in an RLC series circuit refers to:

a)

The frequency at which the inductive reactance equals the capacitive reactance.

b)

The frequency at which the resistance is maximum.

c)

The frequency at which the current is minimum.

d)

The frequency at which the voltage across the inductor is zero.

62.

9b. (i) Mutual inductance is defined as:

a)

The property by which a change in current in one coil induces an emf in another coil placed nearby.

b)

The ability of a coil to resist changes in its own current.

c)

The process of converting electrical energy into mechanical energy.

d)

The phenomenon of current flowing through a resistor.

63.

The coil of an electric generator has 500 turns and 8.0 cm diameter. If it rotates in a magnetic field of density 0.25 T, calculate the angular speed when its peak voltage is 480 V.

a)

Angular speed (ω) = 120 rad/s

b)

Angular speed (ω) = 60 rad/s

c)

Angular speed (ω) = 240 rad/s

d)

Angular speed (ω) = 30 rad/s

64.

Eddy currents are:

a)

currents induced in conductors when exposed to a changing magnetic field

b)

currents that flow only in superconductors

c)

currents that flow in insulators

d)

currents produced by batteries

65.

State two practical uses of eddy currents.

a)

1. Magnetic braking in trains. 2. Induction heating.

b)

1. Generating electricity in solar panels. 2. Cooling electronic devices.

c)

1. Powering electric motors. 2. Producing sound in speakers.

d)

1. Lighting fluorescent bulbs. 2. Charging batteries.

66.

Define critical angle as used in optics.

a)

The critical angle is the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90 degrees.

b)

The critical angle is the angle of refraction in the denser medium for which the angle of incidence in the rarer medium is 90 degrees.

c)

The critical angle is the minimum angle of incidence at which light is completely absorbed by the medium.

d)

The critical angle is the angle at which light passes straight through the boundary without bending.

67.

State two conditions necessary for total internal reflection to occur.

a)

1. Light must travel from a denser to a rarer medium. 2. The angle of incidence must be greater than the critical angle.

b)

1. Light must travel from a rarer to a denser medium. 2. The angle of incidence must be less than the critical angle.

c)

1. Light must travel from a denser to a rarer medium. 2. The angle of incidence must be less than the critical angle.

d)

1. Light must travel from a rarer to a denser medium. 2. The angle of incidence must be greater than the critical angle.

68.

List three practical applications of total internal reflection.

a)

1. Optical fibers. 2. Prisms in binoculars. 3. Diamond sparkle.

b)

1. Solar panels. 2. Loudspeakers. 3. Electric motors.

c)

1. Magnifying glasses. 2. Thermometers. 3. Barometers.

d)

1. Wind turbines. 2. Water pumps. 3. Steam engines.

69.

State two effects of refraction.

a)

1. Bending of light. 2. Apparent depth change in water.

b)

1. Reflection of light. 2. Increase in light speed in all media.

c)

1. Sound amplification. 2. Magnetic field creation.

d)

1. Light absorption. 2. Temperature increase.

70.

Define progressive waves.

a)

A progressive wave is a wave that transfers energy from one point to another without transferring matter.

b)

A progressive wave is a wave that remains stationary and does not transfer energy.

c)

A progressive wave is a wave that transfers matter from one point to another without transferring energy.

d)

A progressive wave is a wave that only exists in solids and not in liquids or gases.

71.

A plane progressive wave is represented by the equation y=0.5sin⁡(1000πt−100πx17)y=0.5\sin(1000\pi t-\frac{100\pi x}{17}) , where y is in millimetres, t in seconds, and x in metres. Calculate the frequency and the wavelength of the wave

a)

F = 250 Hz, λ = 0.17 m;

b)

F = 1000 Hz; λ = 0.34m

c)

F = 100 Hz, λ = 0.17 m;

d)

F = 500 Hz, λ = 0.17 m;

72.

The saturated vapour pressure can be defined as

a)

the pressure exerted by a vapour in equilibrium with its liquid at any temperature.

b)

the pressure exerted by a liquid in equilibrium with its solid at a given temperature.

c)

the pressure exerted by a vapour in equilibrium with its solid at a given temperature.

d)

the pressure exerted by a vapour in equilibrium with its liquid at a given temperature.

73.

When light of frequency 5.4×1014Hz5.4 \times 10^{14} Hz is incident on a metal surface, the maximum energy of the emitted electrons is 1.2×10−19J1.2 \times 10^{-19} J . Calculate the minimum frequency of radiation for which electrons can be emitted.

a)

1.82 x 10^14 Hz

b)

2.70 x 10^14 Hz

c)

4.50 x 101410^{14} Hz

d)

5.40 x 10^14 Hz

74.

What is the primary reason that a lunar eclipse can be seen from anywhere on the night side of the Earth?

a)

The Earth is larger than the Moon.

b)

The Moon passes through the Earth's shadow.

c)

The Earth's atmosphere refracts light.

d)

The Sun is much larger than the Earth.

75.

In the context of the photoelectric effect, what happens to the emitted electrons when the frequency of the incident light is increased?

a)

The number of emitted electrons decreases.

b)

The energy of the emitted electrons increases.

c)

The emitted electrons become negatively charged.

d)

The speed of the emitted electrons decreases.

76.

When two resistors are connected in series, how is the total resistance calculated?

a)

R = R₁ - R₂

b)

R = R₁ × R₂

c)

R = R₁ + R₂

d)

R = 1/(1/R₁ + 1/R₂)

77.
1. A few grains of table salt were put in a cup of cold water, kept at constant temperature and left undistributed. Eventually all the water tested salty. This action is due to?
a)
convection
b)
osmosis
c)
capillarity
d)
diffusion
78.
2. The force required to make an object of mass m, travelling with velocity v, turn in a circle of radius r is
a)
mv2/r
b)
mr2/x
c)
mr/v
d)
mv/r2
79.
3. A machine gun with a mass of 5kg fires a 50g bullet at a speed of 100 ms−1. The recoil speed of the machine gun is
a)
0.5 ms−1
b)
1.5 ms−1
c)
1 ms−1
d)
2ms−1
80.
4. If in a simple pendulum experiment the length of the inextensible string is increased by a factor of four, its period is increased by a factor of?
a)
4
b)
π/2
c)
14
d)
2
81.
5. In what range of temperature is the expansion of water anomalous?
a)
+208C to +212C
b)
-80C to +76C
c)
0C to +4C
d)
-4C to +0C
82.
6. Which of the following statements about radioactivity is true? (i) Alpha particle is positively charged (ii) Beta particle is negatively charged (iii) Gamma ray is neutral (iv) Beta particle has the same mass as helium atom (v) Gamma ray is charged.
a)
i, ii, iii, iv only
b)
i, ii, iii only
c)
iv and v only
d)
i, ii and v only
83.
7. In the study of Physics, temperature and heat are often confused with each other. Which of the following statements correctly defines these two elements?
a)
Temperature is a measure of the average kinetic energy of the molecules of a substance
b)
Heat is a measure of the total kinetic energy of the molecules in a system
c)
Different materials require different amounts of heat to cause a given change in temperature
d)
All of the above
84.
8. The effect of closing the key K in the circuit shown in the figure above would be to?
a)
increase the current by 0.4A
b)
reduce the current by 0.4A
c)
increase the current by 0.6A
d)
reduce the current by 0.6A
85.
9. Which of the following statements on the use of X-rays is incorrect? X-rays are used
a)
In a hospital to obtain photographs of tissues and bones in the body
b)
For the treatment of malignant growths like cancer cells
c)
In detecting fingerprints
d)
To reveal hidden flaws in metal castings and welded joints work of art
86.
10. Natural radioactivity consists of emission?
a)
α -particles and β-rays
b)
α -particles and X-rays
c)
γ -ray and X-rays
d)
α-particles and β-rays and γ
87.
11. If a source of solid is moving, a stationary listener will hear a sound of different frequency. This is called?
a)
doppler effect
b)
resonance
c)
ultra sound
d)
rarefaction
88.
12. Which of the following can be described as high tension transmission?
a)
High resistance and low voltage
b)
Low current and high voltage
c)
High current and low voltage
d)
High current and low resistance
89.
13. What is the cost of running five 50W lamps and four 100W lamps for 10 hours if electrical energy costs 2 Kobo per KWh?
a)
. N0.65
b)

N0.39

c)

N3.90

d)

N0.13

90.
14. The mass of a proton is approximately equal to that of
a)
an α -particle
b)
a β-Particle
c)
a neutron
d)
an electron
91.
15. A transformer has 300 turns of wire in the primary coil and 30 turns in the secondary coil. If the input voltage is 100 volts, the output voltage is
a)
5 volts
b)
10 volts
c)
15 volts
d)
20 volts
92.
16. A solid weighs 4.8g in air, 2.8g in water and 3.2g in Kerosine. The ratio of density of the solid to that of the kerosine is
a)
2
b)
3/2
c)
2/3
d)
3
93.
17. One of the following readings represents the measurement of the length of a metal rod using vernier callipers. Taking the reading accuracy into consideration, the most likely one is
a)
5.16cm
b)
5.165cm
c)
5.0cm
d)
5.160cm
94.
18. When a sound wave passes from air into water its
a)
speed and frequency increases but its wavelength remains the same
b)
speed and wavelength increases but its frequency remains the same
c)
speed decreases
d)
speed increases but its frequency and wavelength decreases
95.
19. A convex mirror is used as a driving mirror because its I. image is erect II. It has a large field of view III. It has a long focal length Identify the CORRECT statement(s)
a)
A. I and III only
b)
I and II only
c)
II and IIII only
d)
I, II and III only
96.
20. Two mirrors of the same length are arranges as show in the diagram below. A ray of light NO strikes the system at O and emerges along PQ. The emergent ray has been deviated through
a)
220
b)
200
c)
210
d)
180
97.
21. A magnetic needle is suspended first at the earth's north magnetic pole and then at a point on the magnetic equator. The respective angles between the needle and the horizontal are
a)
0o and 0o
b)
60o and 60o
c)
90o and 90o
d)
90o to 0o
98.
22. A hydrometer is an instrument for measuring the
a)
a depth of water of water in a vessel
b)
relative density of a liquid by the method of flotation
c)
relative density of a liquid by finding the apparent loss in weight
d)
relative humidity of the air
99.
23. Consider the three forces acting at O and in equilibrium as shown in the figure. Which of the following equations is/are CORRECT? I. P1 cos θ1 = p1 cos θ2 II. P3 = P1 cos θ4 + P2cos2 III. P1sinθ1=P2sinθ2
a)
I only
b)
II only
c)
III only
d)
I, II and III only
100.
24. The refractive index of a liquid is 1.5. If the velocity of light in vacuum is 3.0 x 10^8ms−1, the velocity of light in the liquid is
a)
1.5 x 10^8ms−1
b)
2.0 x 10^8ms−1
c)
3.0 x 10^8ms−1
d)
4.5 x 10^8ms−1
101.
25. A ship travelling towards a cliff receives the echo of its whistle after 3.5 seconds. A short while later, it receives the echo after 2.5 seconds. If the speed of sound in air under the prevailing condition is 250ms -1, how much closer is the ship to the cliff?
a)
10m
b)
350m
c)
175m
d)
125m
102.
26. Which of the following statements about defects of vision is/are CORRECT? I. For a long sighted person, close objects appear blurred II. For a short sighted person, distant objects appear blurred III. Short sight is corrected by using a pair of converging lenses
a)
I only
b)
II only
c)
I and II only
d)
II and III only
103.

27. Which of the following conditions are necessary and sufficient for total internal reflection to take place at the boundary between two optical media?

I. Light is passing from optical denser medium to optically less dense medium II. Light is passing from optically less dense medium to optically denser medium III. Angle of incidence is greater than a certain critical value IV. Angle of incidence is lesser than a certain critical value

a)
I and II only
b)
II only III only
c)
III and IV only
d)
I and III only
104.
28. The linear expansivity of brass is 2 x 10−5 oC−1. If the volume of piece of brass is 10cm3 at 0oC. What will be its volume at 100oC?
a)
10.06cm3
b)
10.04 cm3
c)
10.02 cm3
d)
10.20 cm3
105.
29. The lower and upper fixed points marked on a Mercury-in-glass thermometer are 210mm apart. The end of the mercury column in the tube is 49mm above the lower fixed point in a room. What is the temperature of the room in degrees Celsius?
a)
55.3oC
b)
23.3oC
c)
49.0oC
d)
16.43oC
106.
30.
a)
A
b)
B
c)
C
d)
D
107.
31. Two divers G and H are at depths 20m and 40m, respectively below the water surface in a lake. The pressure on G is p1 while the pressure on H is P2, If the atmospheric pressure is equivalent to 10m of water, then the value of P2/P1 is?
a)
0.50
b)
0.60
c)
1.67
d)
2.00
108.
32. The figure below represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is 40%, then the value of W is
a)
28.0N
b)
48.0N
c)
288.0N
d)
50.0N
109.
33. In an experiment in which molten naphthalene is allowed to cool, the cooling curve in the figure below was obtained. The temperature 80oC is known as the
a)
cooling temperature
b)
boiling point
c)
melting point
d)
vaporization point
110.
34. In the figure, the value of R is
a)
3Ω
b)
6Ω
c)
4Ω
d)
5Ω
111.
35.
a)
I
b)
II
c)
III
d)
IV
112.
36. In which of the following diagrams is the length of the tube equal to three-quarter wavelength?
a)
I
b)
II
c)
III
d)
IV
113.
37. Which of the following pairs is part of the electromagnetic spectrum? I. Radio waves II. sound waves III. Gamma rays IV. water waves
a)
I and II
b)
III and IV
c)
I and III
d)
II and IV
114.
38. A substance has half of 3 min. After 6 min, the count rate was observed to be 400. What was its count rate at zero time?
a)
1600
b)
1200
c)
200
d)
2400
115.
39. In alternating current circuit at resonance, the angle of lead or lag is?
a)
. π°
b)
(π)/2°
c)
(π)/3°
d)
0°
116.
40. In a series R-L-C circuit at resonance, the voltages across the resistor and the inductor are 30V and 40V respectively. What is the voltage across the capacitor?
a)
30V
b)
70V
c)
50V
d)
40V
117.

Which of the following statements is true of the law of universal gravitation?

a)

Any two bodies attract each other with a force proportional to the difference of their masses.

b)

Any two bodies attract each other with a force inversely proportional to the square of the distance between them.

c)

Any two bodies attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.

d)

Any two bodies attract each other with a force proportional to the square of the distance between them.

118.

Which of the following is true of an electrical charge?

a)

Positive charge means deficit of electrons.

b)

Negative charge means excess of electrons.

c)

Electric current is the movement of electrons.

d)

All of the above.

119.

Which of the following statements are true about the structure of atoms?

a)

Atoms of different elements differ only in the number of protons and electrons.

b)

The number of protons equals the number of electrons in a neutral atom.

c)

Atoms are constructed according to the plan of the solar system.

d)

All of the above.

120.

Which of the following are true of atoms?

a)

Atoms are indestructible.

b)

All atoms of an element are identical.

c)

Atoms of different elements have different weights.

d)

All of the above.

121.

A magnet is similar to a bipolar charged system because

a)

it consists of two opposite poles — north and south.

b)

the Earth has magnetic poles near the geographical poles.

c)

the force between poles obeys a law similar to electrostatic forces.

d)

A and C only.

122.

Which of the following correctly defines temperature and heat?

a)

Temperature is a measure of the average kinetic energy of molecules.

b)

Heat is a measure of the total kinetic energy of molecules in a system.

c)

Different materials require different amounts of heat to cause a given temperature change.

d)

All of the above.

123.

The ratio of the specific heat capacity of oil to that of water is

a)

0.36

b)

0.46

c)

0.56

d)

0.76

124.

Which of the following is NOT a vector quantity?

a)

Velocity

b)

Work

c)

Force

d)

Electric field intensity

125.

The motion of the skin of a talking drum is

a)

translational

b)

random

c)

rotational

d)

oscillatory

126.

Which of the following does NOT reduce the surface tension of water?

a)

Soap solution

b)

Detergent

c)

Alcohol

d)

Grease

127.

Water at the bottom of a waterfall is slightly warmer because part of the

a)

potential energy raises the temperature.

b)

water absorbs latent heat from the atmosphere.

c)

kinetic energy is converted into internal energy.

d)

A and C only.

128.

A pressure cooker saves time and fuel because inside it

a)

the boiling point of water is raised.

b)

pressure is constant.

c)

heat is completely trapped.

d)

temperature is evenly distributed.

129.

Which of the following is NOT true of the image formed by a plane mirror? The image is

a)

the same size as the object.

b)

laterally inverted.

c)

virtual.

d)

magnified.

130.

Any line joining points on a wave that are in the same phase is called a

a)

wavelength.

b)

crest.

c)

amplitude.

d)

wavefront.

131.

The property by which substances align perpendicular to a strong magnetic field is

a)

magnetization.

b)

paramagnetism.

c)

diamagnetism.

d)

ferromagnetism.

132.

Which of the following is NOT a use of X-rays?

a)

Medical imaging

b)

Treatment of cancer

c)

Detecting fingerprints

d)

Detecting flaws in metals

133.

The relative permittivity of a capacitor is

a)

12

b)

2

c)

8

d)

32

134.

The energy used by the generator is

a)

3.84 kWh

b)

7.20 kWh

c)

8.40 kWh

d)

12.00 kWh

135.

The ornament is made of

a)

Zinc

b)

Brass

c)

Copper

d)

Gold

136.

If volume is constant, pressure is

a)

inversely proportional to centigrade temperature.

b)

inversely proportional to absolute temperature.

c)

directly proportional to centigrade temperature.

d)

directly proportional to absolute temperature.

137.

Which of the following about sound is NOT true?

a)

Sound is a longitudinal wave.

b)

Sound can be reflected and refracted.

c)

Sound travels through a vacuum.

d)

Sound travels faster in steel than in air.

138.

In a compound microscope

a)

there is only one lens.

b)

the objective has shorter focal length than the eyepiece.

c)

the objective has longer focal length than the eyepiece.

d)

both lenses have the same focal length.

139.

A blue flower appears blue because it

a)

disperses light.

b)

absorbs blue light.

c)

refracts blue light.

d)

reflects blue light.

140.

High-tension transmission means

a)

transmission at low current and high voltage.

b)

heat is not lost.

c)

a large transformer is required.

d)

transmission at high current.

141.

The best material for the core of an induction coil is

a)

copper.

b)

steel.

c)

soft iron.

d)

glass.

142.

Which radiation cannot be deflected by a magnetic field?

a)

Alpha

b)

Beta

c)

Gamma

d)

None

143.

The best absorber of X-rays is

a)

Hydrogen

b)

Oxygen

c)

Copper

d)

Lead

144.

According to Ohm’s law, V/I is constant for

a)

an electrolyte

b)

a diode

c)

a transistor

d)

silver

145.

In electrification by induction, the induced charge is

a)

same in sign and quantity.

b)

same in sign but greater.

c)

opposite in sign but equal.

d)

opposite in sign but less.

146.

The activity of a radioactive substance depends on

a)

temperature and purity.

b)

purity and age.

c)

age only.

d)

none of the above.

147.

Unform speed occurs when there is equal change of ________

a)

distance in equal times

b)

displacement in equal time

c)

velocity in equal times

d)

acceleration in equal times

148.

During the same time interval, it is observed that a train travels the same distance as does a lorry. The two vehicles therefore have the same_______

a)

Uniform acceleration

b)

Average velocity

c)

Initial velocity

d)

Average speed

149.

The speed of a body in a given direction is _______

a)

acceleration

b)

speed

c)

velocity

d)

average speed

150.

The term rectilinear acceleration means the rate of increase of

a)

Velocity along a circular path and in a unit time

b)

distance along a rectangular path in unit time.

c)

displacement along a straight-line path in unit time.

d)

velocity along a straight-line path in unit time.

151.

What is the difference between the velocity and the speed of an object?

a)

Velocity is the change in distance over time, while speed is the change

velocity over time.

b)

Velocity has a direction associated with it, while speed has no specific

direction.

c)

Velocity has no direction associated with it, while speed has a specific

direction.

d)

Velocity is the change in speed over time, while speed is the change in

distance over time.

152.

Change in speed or velocity over a specific amount of time

a)

acceleration

b)

velocity

c)

average speed

d)

speed

153.

A moving body is said to have uniform acceleration if its

a)

displacement decreases at constant rate.

b)

Velocity changes by equal amount in equal time intervals

c)

Velocity varies inversely with time

d)

Speed is directly proportional to time

154.

The quantity of motion of a body is _________

a)

Acceleration

b)

Displacement

c)

Momentum

d)

Velocity

155.

The time rate of change of displacement is called______

a)

speed

b)

velocity

c)

impulse

d)

Acceleration

156.

A body moving at constant speed accelerates when it is in_______

a)

rectilinear motion

b)

Translational motion

c)

Circular motion

d)

Vibrational motion

157.

Which of the following statements is not correct?

a)

Speed is the rate of change of distance

b)

Velocity is the speed in a particular direction

c)

Acceleration is the time rate of change of speed in a given direction

d)

The acceleration of a body with unform velocity increases with time

158.

Two blocks of the same dimensions, one steel and the other wooden, are dropped simultaneously from the same height. If they fall freely neglecting air resistance the

a)

two blocks hit the ground simultaneously because they have the same acceleration.

b)

Two blocks reach the ground at the same time because of their dimensions are the same

c)

wooden block being lighter than the steel block reaches the ground first

d)

steel block reaches the ground first because it is denser than the wooden block

159.

A body starts from rest and accelerates uniformly for 3s at the rate of 5 ms−2ms^{-2} . Find the final velocity

a)

2m/s

b)

5/3 m/s

c)

15m/s

d)

10m/s

160.

From the diagram, determine the maximum distance covered by the car

a)
40m
b)
3m
c)
20m
d)
10m
161.

From the diagram, at what point in the graph does the car have the highest speed?

a)
A
b)
B
c)
C
d)
D
162.

From the graph, evaluate the total distance travelled by the vehicle

a)
20m
b)
25m
c)
40m
d)
30m
163.

Using the graph, determine the distance covered after 5s.

a)
10m
b)
20m
c)
15m
d)
5m
164.
6. Calculate the speed of the body in line B
a)
2m/s
b)
0.5m/s
c)
1m/s
d)
5m/s
165.

The slope of a velocity - time graph represents?

a)

Velocity

b)

Displacement

c)

Acceleration

d)

Time

166.

The area between the x-axis and the line of a velocity - time graph represents?

a)

Velocity

b)

Displacement

c)

Acceleration

d)

Time

167.

Which of the following is not a quantity used in equation of motion?

a)

Velocity

b)

Position

c)

Time

d)

Acceleration

168.

The slope of straight line distance time graph shows _______

a)

Velocity

b)

Uniform Displacement

c)

Constant Acceleration

d)

Constant speed

169.

What is the distance covered by a bullet fired from a gun at a velocity of 20m/s if passes through water until it velocity becomes 15m/s in 10 seconds?

a)

150m

b)

170m

c)

140m

d)

175m

170.
Which of the following is accelerating?
a)
A cannonball sitting on the ground
b)
A boat traveling at a constant speed in a straight line
c)
A can being crushed under a person's foot
d)
A car going around a curve at a constant speed
171.

A spring has a spring constant of 5N/m.  What is the extension produced when loaded with a 15N force?

a)
4cm
b)
5cm
c)
3m
d)
3cm
172.
An unstretched spring has a length of 0.10 meters. When the spring is stretched by a force of 16 newtons, its length is increased to 0.18 meters. What is the spring constant of this spring? 
a)

0.89 N/m 

b)

2.0 N/m 

c)

1.6 N/m 

d)

1.8 N/m

173.

The gravitational field strength on Jupiter is about 2 times the gravitational field strength on Earth. If an object has a mass of 50 kg and a weight of 500 N on Earth, what would be the object's approximate mass and weight on Jupiter?

a)

50 kg and 500 N

b)

100 kg and 500 N

c)

50 kg and 1000 N

d)

100 kg and 1000 N

174.

The gravitational field strength on Jupiter is about 2 times the gravitational field strength on Earth. If an object has a mass of 50 kg and a weight of 500 N on Earth, what would be the object's approximate mass and weight on Jupiter?

a)

50 kg and 500 N

b)

100 kg and 500 N

c)

50 kg and 1000 N

d)

100 kg and 1000 N

175.

Which of the following pairs of units are the same?

a)

watt and joule

b)

J/s and Pascal

c)

kgms−2 and Newtonkgms^{-2}\ and\ Newton

d)

kg2m2 and Joulekg^2m^2\ and\ Joule

176.

By increasing the distance between an object and the earth's surface , so the weight of this object ...........

a)

decreases

b)

increases

c)

not effected

d)

still constant

177.

What is surface tension and how does it affect liquid behavior?

a)

Surface tension is the force that pulls liquids downwards.

b)

Surface tension is the cohesive force at the surface of a liquid that causes it to behave as if it were covered by an elastic membrane.

c)

Surface tension is the temperature at which a liquid boils.

d)

Surface tension is the pressure exerted by a gas above a liquid.

178.

Explain the concept of cohesion in liquids.

a)

Cohesion in liquids is the attraction between similar molecules that keeps them together.

b)

Cohesion in liquids is the repulsion between different molecules.

c)

Cohesion is the force that causes liquids to freeze at low temperatures.

d)

Cohesion refers to the ability of liquids to evaporate quickly.

179.

What is adhesion and how does it differ from cohesion?

a)

Adhesion and cohesion are both types of chemical bonds between identical substances.

b)

Adhesion is the attraction between different substances; cohesion is the attraction between similar substances.

c)

Adhesion refers to the repulsion between different substances; cohesion is the attraction between similar substances.

d)

Adhesion is the attraction between similar substances; cohesion is the attraction between different substances.

180.

Provide an example of adhesion in everyday life.

a)

Water droplets on a leaf.

b)

Oil spreading on water

c)

A magnet sticking to a fridge

d)

Sugar dissolving in coffee

181.

How does temperature affect surface tension in liquids?

a)

Temperature increases surface tension in liquids.

b)

Temperature has no effect on surface tension in liquids.

c)

Temperature decreases surface tension in liquids.

d)

Temperature only affects the viscosity of liquids.

182.

What's the value of the intercept on the horizontal axis from the graph?

a)

0K

b)

273K

c)

-273⁰C

d)

273K

183.

Which of the following best describes Gay-Lussac's law?

a)

The pressure of a gas remains constant regardless of temperature changes.

b)

The pressure of a gas increases with an increase in temperature at constant volume.

c)

The temperature of a gas decreases with an increase in pressure at constant volume.

d)

The volume of a gas increases with an increase in pressure at constant temperature.

184.

Which of the following set of quantities are fundamental?

a)

Pressure, length and Electric current

b)

Mass, Length, and frequency

c)

Length, Time, Mass and angle

d)

None of the above

185.

Which of the following is a quantity of motion?

a)

Mass

b)

Velocity

c)

Moment

d)

Momentum

186.

Which of the following is the dimension of force?

a)

MLT²

b)

Newton (N)

c)

kgms-²

d)

MLT-²

187.

Which of the following is a vector quantity?

a)

Pressure

b)

electric potential

c)

Magnetic flux

d)

Work

188.

What is the unit of pressure in physics?

a)

N²/m

b)

Pascal (Pa)

c)

N/m³

d)

N/m

189.

What is the role of surface tension in the formation of droplets?

a)

Surface tension causes liquids to spread out instead of forming droplets.

b)

Surface tension increases the size of droplets.

c)

Surface tension causes liquids to form droplets by minimizing surface area.

d)

Surface tension has no effect on droplet formation.

190.

How does cohesion contribute to the properties of water?

a)

Cohesion reduces water's density when frozen.

b)

Cohesion contributes to water's high surface tension and temperature stability.

c)

Cohesion makes water a poor solvent.

d)

Cohesion decreases water's boiling point.

191.

Explain how adhesion is important in the process of capillary action.

a)

Adhesion only occurs in solid materials.

b)

Adhesion allows liquid to climb surfaces, enabling capillary action.

c)

Adhesion has no effect on capillary action.

d)

Adhesion prevents liquids from climbing surfaces.

192.
a)

7.8kN, 300

b)

4.5kN, 650

c)

6.8kN, 580

d)

8kN, 1050

193.

Find the horizontal component of the system of forces in the diagram if the 30N forces makes an angle of 600 with the negative x-axis.

a)

80N due South

b)

35N due East

c)

75.98N due West

d)

65N due East

194.

The change in volume when 450 kg of ice is completely melted is (Density of ice = 900 kg m⁻³, Density of water = 1000 kg m⁻³)

a)

0.50 m³

b)

0.45 m³

c)

0.05 m³

d)

4.50 m³

195.

The qualities of a good thermometer include

a)

I, II and IV only

b)

I, III and IV only

c)

I, II and III only

d)

II, III and IV only

196.

In a good thermos flask, heat loss is reduced through the following features EXCEPT

a)

the lens surface

b)

the insulating cork

c)

silvered walls

d)

the cork lid

197.

The thermometer whose reading is indicated by a change in colour of its thermometric property is the

a)

bi-metallic strip thermometer

b)

thermocouple

c)

platinum resistance thermometer

d)

optical pyrometer

198.

A heating coil rated 1000 W is used to boil off completely 2 kg of boiling water. The time required is (Specific latent heat of vaporization of water = 2.3 × 10⁶ J kg⁻¹)

a)

1.15 × 10⁴ s

b)

1.15 × 10³ s

c)

4.6 × 10⁴ s

d)

4.6 × 10³ s

199.

A man standing 2 m from a charcoal fire is warmed mainly by

a)

convection

b)

radiation

c)

refraction

d)

conduction

200.

If a container is filled with ice to the brim, what happens to the level of water when the ice completely melts?

a)

the level of water goes up

b)

the water overflows

c)

the level remains unchanged

d)

the level drops

201.

Which of the following has no effect on radiation?

a)

nature of surface

b)

density

c)

surface area

d)

temperature

202.

Steel bars each of length 3 m at 28°C are used for constructing a rail line. If the linear expansivity is 1 × 10⁻⁵ K⁻¹ and the highest temperature expected is 40°C, the safety gap is

a)

1.2 × 10⁻¹ cm

b)

7.2 × 10⁻¹ cm

c)

6.0 × 10⁻¹ cm

d)

3.6 × 10⁻² cm

e)

1.8 × 10⁻¹ cm

203.

Which of the following statements are correct? i. Land and sea breezes are natural convection currents ii. Convection may occur in liquids or gases but not in solids iii. The vacuum in a thermos flask prevents heat loss due to convection only

a)

i and ii only

b)

i and iii only

c)

ii and iii only

d)

i, ii and iii

204.

A hot metal ball suspended in the open air loses heat by

a)

conduction only

b)

convection only

c)

radiation only

d)

conduction and convection

e)

convection and evaporation

205.

A waterfall is 420 m high. Calculate the difference in temperature between the top and bottom (g = 10 m s⁻², specific heat capacity of water = 4.20 × 10³ J kg⁻¹ K⁻¹)

a)

0.1°C

b)

1.0°C

c)

42°C

d)

100°C

e)

4.20°C

206.

A waterfall is 1260 m high. Calculate the change in temperature of the water (g = 10 m s⁻², specific heat capacity = 4200 J kg⁻¹ K⁻¹)

a)

0.3°C

b)

3.0°C

c)

33.3°C

d)

42.0°C

e)

100.0°C

207.

The mass of an empty density bottle is 30 g. When filled, its mass is 40 g. After heating through 40°C, the mass reduces to 38 g. Calculate the apparent cubic expansivity of the liquid

a)

6.25 × 10 K⁻¹

b)

6.25 × 10⁻³ K⁻¹

c)

2.50 × 10⁻³ K⁻¹

d)

2.50 × 10⁻⁴ K⁻¹

208.

A gas occupies a certain volume at 27°C. At what temperature will its volume be twice the original volume, assuming constant pressure?

a)

54°C

b)

108°C

c)

150°C

d)

327°C

e)

600°C

209.

A metal rod has a length of 100 cm at 200°C. At what temperature will its length be 99.4 cm if the linear expansivity is 2 × 10⁻⁵ °C⁻¹

a)

300°C

b)

200°C

c)

100°C

d)

−100°C

210.

Which of the following thermometers is used to measure the temperature of the human body?

a)

Thermocouple

b)

Alcohol-in-glass thermometer

c)

Gas thermometer

d)

Platinum resistance thermometer

211.

The length of an iron bar is 100 cm at 20°C. At what temperature will its length increase by 0.01%? (Linear expansivity = 1.2 × 10⁻⁵ °C⁻¹)

a)

48.0°C

b)

38.0°C

c)

28.3°C

d)

23.0°C

212.

A metallic sphere is heated from 27°C to 200°C without change of state. Which change occurs?

a)

No change in volume and density

b)

Volume increases and density increases

c)

Volume increases and density decreases

d)

Volume increases without change in density

213.

The distance between the fixed points of a mercury-in-glass thermometer is 30 cm. Determine the temperature when the mercury level is 10.5 cm above the lower fixed point

a)

28.6°C

b)

30.0°C

c)

35.0°C

d)

40.5°C

214.

Which of the following methods of heat transfer does not require a material medium?

a)

Conduction

b)

Diffusion

c)

Convection

d)

Radiation

215.

A quantity of water at 0°C is heated to 30°C. For each degree rise in temperature, its density will

a)

rise steadily

b)

fall steadily

c)

fall and then rise

d)

rise and then fall

216.

The relationship between the coefficient of linear expansion (α) and volumetric expansion (γ) is

a)

γ = α − 3

b)

γ = α

c)

γ = 3α

d)

γ = α³

217.

The amount of energy required to change 1 kg of ice into water without temperature change is

a)

specific latent heat of fusion of ice

b)

specific heat capacity of ice

c)

heat capacity of ice

d)

specific latent heat of vaporization of ice

218.

According to the kinetic theory of gases, gas pressure is equal to

a)

change in momentum per unit volume

b)

rate of change of momentum per second per unit area

c)

momentum imparted per unit area

d)

change in momentum per unit area

219.

A gas of volume V₀ at pressure P₀ is compressed to one-fifth of its volume at constant temperature. The new pressure is

a)

P₀/5

b)

4P₀/5

c)

P₀

d)

5P₀

220.

At a fixed point below a liquid surface, the downward pressure is P₁ and the upward pressure is P₂. It can be deduced that

a)

P₁ > P₂

b)

P₁ ≥ P₂

c)

P₁ < P₂

d)

P₁ = P₂

221.

When cold water is poured on a can containing hot water, the can collapses because

a)

steam condenses and occupies the vacuum

b)

external pressure balances internal pressure

c)

steam expands into the vacuum

d)

external pressure becomes greater than internal pressure

222.

The thermometric property of a thermocouple is the change in

a)

resistance

b)

electromotive force

c)

colour

d)

pressure

223.

During summer, the balance wheel of a clock expands. The effect on the accuracy of the clock is that

a)

the clock gains time

b)

accuracy is not affected

c)

the clock loses time

d)

the clock stops

224.

If the pressure of the vapour on top of an enclosed liquid is equal to the atmospheric pressure, the temperature of the liquid enclosed is

a)

room temperature

b)

boiling point

c)

freezing point

d)

standard temperature

225.

In a hydraulic press, the pump piston exerts a pressure of 100 Pa on the liquid. What force is exerted on the second piston of cross-sectional area 3 m²?

a)

300 N

b)

200 N

c)

150 N

d)

100 N

226.

One special advantage of alcohol over mercury as a thermometric liquid is its

a)

low density

b)

low freezing point

c)

high specific heat capacity

d)

low boiling point

227.

Heat is radiated by hot objects in the form of

a)

X-rays

b)

light energy

c)

infrared rays

d)

solar energy

228.

The pressure of one mole of an ideal gas of volume 1.0 × 10⁻² m³ at 27°C is (Molar gas constant = 8.3 J mol⁻¹ K⁻¹)

a)

2.49 × 10⁴ N m⁻²

b)

2.24 × 10⁴ N m⁻²

c)

2.49 × 10⁵ N m⁻²

d)

2.24 × 10⁵ N m⁻²

229.

A blacksmith heated a metal whose cubic expansivity is 6.3 × 10⁻⁶ K⁻¹. The area expansivity is

a)

2.0 × 10⁻⁶ K⁻¹

b)

2.1 × 10⁻⁶ K⁻¹

c)

4.2 × 10⁻⁶ K⁻¹

d)

6.3 × 10⁻⁶ K⁻¹

230.

The pressure of two moles of an ideal gas at 27°C and volume 1.0 × 10⁻² m³ is (R = 8.313 J mol⁻¹ K⁻¹)

a)

4.99 × 10⁵ N m⁻²

b)

9.80 × 10³ N m⁻²

c)

4.98 × 10³ N m⁻²

d)

9.80 × 10⁵ N m⁻²

231.

Two metals P and Q of lengths l₁ and l₂ are heated through the same temperature difference. If the ratio of their linear expansivities is 2: 3 and the ratio of their lengths is 3: 4, what is the ratio of increase in length of P to Q?

a)

7: 5

b)

5: 7

c)

1: 2

d)

2: 1

232.

The expansion of solids can be considered a disadvantage in the

a)

balance wheel of a watch

b)

fitting of wheels on rims

c)

fire alarm

d)

thermostat

233.

Two divers G and H are at depths 20 m and 40 m respectively below the water surface in a lake. The pressure on G is P₁ while that on H is P₂. If atmospheric pressure is equivalent to 10 m of water, the value of P₂/P₁ is

a)

0.50

b)

0.60

c)

1.67

d)

2.00

e)

3.0

234.

A quantity of gas occupies a certain volume when the temperature is −73°C and the pressure is 1.5 atmospheres. If the pressure is increased to 4.5 atmospheres and the volume is halved, the new temperature is

a)

573°C

b)

327°C

c)

300°C

d)

110°C

e)

27°C

235.

When a fixed mass of an ideal gas expands at constant temperature, which property of the gas molecules increases?

a)

average number per unit volume

b)

average kinetic energy

c)

average separation

d)

average number of collisions per unit time

236.

If the volume of a fixed mass of gas is kept constant, the pressure of the gas

a)

is inversely proportional to its centigrade temperature

b)

is inversely proportional to its absolute temperature

c)

is directly proportional to its centigrade temperature

d)

is directly proportional to its absolute temperature

e)

remains constant

237.

An object is heated from 30°C to 57°C. The increase in temperature on the Kelvin scale is

a)

17 K

b)

27 K

c)

81 K

d)

246 K

e)

300 K

238.

One common characteristic of solids, liquids and gases is that

a)

all have fixed volume

b)

their molecules have the same size

c)

their molecules are always in motion

d)

all have the same intermolecular forces

239.

Which of the following best describes the energy changes when a steam engine drives a generator which lights a lamp?

a)

Heat → Light → Sound → Kinetic

b)

Kinetic → Light → Heat → Electricity

c)

Heat → Kinetic → Electricity → Heat and Light

d)

Electricity → Kinetic → Heat → Light

240.

A force of 10 N moves an object through a distance of 5 m in the direction of the force. The work done is

a)

2 J

b)

15 J

c)

50 J

d)

100 J

241.

Which of the following is a unit of power?

a)

Joule

b)

Watt

c)

Newton

d)

Kilogram

242.

Work is said to be done when a force

a)

acts on a body at rest

b)

produces motion in its direction

c)

changes the shape of a body only

d)

balances another force

243.

An object of mass 2 kg is raised to a height of 10 m. If g = 10 m/s², the gravitational potential energy gained is

a)

20 J

b)

100 J

c)

200 J

d)

400 J

244.

The principle of conservation of energy states that energy

a)

can be created but not destroyed

b)

can be destroyed but not created

c)

is neither created nor destroyed but transformed

d)

is always lost as heat

245.

A machine is said to be efficient if it

a)

has no friction

b)

does more work than input

c)

has high mechanical advantage

d)

converts most input energy to useful output

246.

Which of the following is an example of a first-class lever?

a)

Wheelbarrow

b)

Nutcracker

c)

Seesaw

d)

Fishing rod

247.

Mechanical advantage of a machine is defined as

a)

load ÷ effort

b)

effort ÷ load

c)

distance moved by load ÷ distance moved by effort

d)

work output ÷ work input

248.

The velocity ratio of a machine is always

a)

less than 1

b)

equal to efficiency

c)

greater than or equal to mechanical advantage

d)

equal to mechanical advantage

249.

Which machine is used to multiply force?

a)

Thermometer

b)

Inclined plane

c)

Spring balance

d)

Stopwatch

250.

Hooke’s law states that extension is directly proportional to the applied force provided that

a)

the load is heavy

b)

the elastic limit is exceeded

c)

the elastic limit is not exceeded

d)

the material is metallic

251.

Stress is defined as

a)

force × area

b)

force ÷ area

c)

area ÷ force

d)

extension ÷ original length

252.

Strain has no unit because it is

a)

very small

b)

difficult to measure

c)

a ratio of two lengths

d)

measured in newtons

253.

The gradient of a load–extension graph represents

a)

strain

b)

elastic limit

c)

modulus of elasticity

d)

breaking point

254.

The point beyond which a material will not return to its original length is the

a)

proportional limit

b)

elastic limit

c)

yield point

d)

breaking point

255.

Pressure is defined as

a)

force × area

b)

force ÷ area

c)

area ÷ force

d)

mass × acceleration

256.

Pascal’s principle is applied in the operation of the

a)

barometer

b)

hydraulic press

c)

thermometer

d)

spring balance

257.

The SI unit of pressure is

a)

Newton

b)

Pascal

c)

Joule

d)

Watt

258.

A body floats in a liquid when the upthrust is

a)

less than the weight

b)

greater than the weight

c)

equal to the weight

d)

zero

259.

Archimedes’ principle states that a body immersed in a fluid experiences an upthrust equal to the

a)

volume of the body

b)

density of the fluid

c)

weight of fluid displaced

d)

mass of fluid displaced

260.

Heat is a form of energy that

a)

has mass

b)

flows from cold to hot bodies

c)

depends on temperature difference

d)

is measured in degrees Celsius

261.

Temperature is a measure of the

a)

heat content of a body

b)

average kinetic energy of particles

c)

mass of a body

d)

total internal energy

262.

Which instrument uses the principle of thermal expansion?

a)

Barometer

b)

Thermometer

c)

Hygrometer

d)

Hydrometer

263.

The expansion of solids when heated is known as

a)

linear expansion

b)

real expansion

c)

apparent expansion

d)

superficial contraction

264.

Gaps are left between rails on railway tracks to

a)

reduce friction

b)

allow for contraction

c)

prevent rusting

d)

allow for expansion

265.

Heat transfer through solids mainly occurs by

a)

radiation

b)

convection

c)

conduction

d)

evaporation

266.

Convection occurs mainly in

a)

solids

b)

liquids and gases

c)

metals only

d)

vacuum

267.

Heat transfer that does not require a medium is

a)

conduction

b)

convection

c)

evaporation

d)

radiation

268.

The shiny surface of a vacuum flask reduces heat loss by

a)

conduction

b)

convection

c)

radiation

d)

evaporation

269.

Land breeze occurs at night because

a)

land cools faster than sea

b)

sea cools faster than land

c)

air pressure over sea is higher

d)

wind blows randomly

270.

Boyle’s law states that for a fixed mass of gas at constant temperature, pressure is

a)

directly proportional to volume

b)

inversely proportional to volume

c)

equal to volume

d)

independent of volume

271.

Charles’ law relates volume of a gas to its

a)

pressure

b)

density

c)

temperature

d)

mass

272.

The pressure law states that pressure of a gas is directly proportional to its

a)

volume

b)

temperature

c)

density

d)

mass

273.

The ideal gas equation is written as

a)

PV = RT

b)

V = PT

c)

P = VRT

d)

PV = nRT

274.

Gas laws are best explained using the

a)

wave theory

b)

atomic theory

c)

kinetic theory

d)

caloric theory

275.

The kinetic theory assumes that particles of matter are in

a)

fixed positions

b)

continuous motion

c)

random arrangement only

d)

circular motion

276.

Increase in temperature of a gas results in

a)

decrease in kinetic energy

b)

constant kinetic energy

c)

increase in kinetic energy

d)

loss of particles

277.

Gas pressure is due to

a)

weight of the gas

b)

attraction between molecules

c)

collision of molecules with container walls

d)

expansion of gas molecules

278.

The kinetic theory explains gas laws because it relates pressure to

a)

mass of gas

b)

motion of particles

c)

density of gas

d)

colour of gas

279.

Which assumption is correct about gas molecules?

a)

They occupy large volumes

b)

They attract one another strongly

c)

Their collisions are perfectly elastic

d)

They are stationary

280.

A machine has a load of 600 N and an effort of 150 N. The mechanical advantage is

a)

2

b)

3

c)

4

d)

6

281.

If the velocity ratio of a machine is 5 and its mechanical advantage is 4, the efficiency of the machine is

a)

20%

b)

40%

c)

80%

d)

125%

282.

A pulley system raises a load of 400 N through 2 m when the effort moves through 8 m. The velocity ratio is

a)

2

b)

4

c)

6

d)

8

283.

The efficiency of a machine that has a velocity ratio of 6 and mechanical advantage of 3 is

a)

25%

b)

50%

c)

75%

d)

100%

284.

Which of the following quantities is used in calculating the efficiency of a machine?

a)

Load only

b)

Effort only

c)

Mechanical advantage and velocity ratio

d)

Distance moved by load only

285.

A metal rod of length 2.0 m expands by 4.0 × 10⁻³ m when heated through 100°C. The linear expansivity of the metal is

a)

2.0 × 10⁻⁵ °C⁻¹

b)

4.0 × 10⁻⁵ °C⁻¹

c)

2.0 × 10⁻⁴ °C⁻¹

d)

4.0 × 10⁻⁴ °C⁻¹

286.

The superficial expansivity of a solid is approximately

a)

equal to the linear expansivity

b)

half the linear expansivity

c)

twice the linear expansivity

d)

three times the linear expansivity

287.

The cubic expansivity of a solid is

a)

equal to the linear expansivity

b)

twice the linear expansivity

c)

three times the linear expansivity

d)

half the superficial expansivity

288.

A cube of metal has a volume of 0.01 m³ at 0°C. If its cubic expansivity is 6 × 10⁻⁵ °C⁻¹, the increase in volume when heated to 100°C is

a)

6 × 10⁻⁶ m³

b)

6 × 10⁻⁵ m³

c)

6 × 10⁻⁴ m³

d)

6 × 10⁻³ m³

289.

When the temperature of a solid increases, its volume expansion depends on

a)

mass only

b)

shape only

c)

temperature change and cubic expansivity

d)

density only

290.

Apparent expansion of a liquid occurs because

a)

the liquid contracts

b)

the container does not expand

c)

both liquid and container expand

d)

temperature remains constant

291.

The real cubic expansivity of a liquid is

a)

less than the apparent cubic expansivity

b)

equal to the apparent cubic expansivity

c)

greater than the apparent cubic expansivity

d)

zero at all temperatures

292.

Real cubic expansivity of a liquid is equal to

a)

apparent expansivity − cubical expansivity of container

b)

apparent expansivity + cubical expansivity of container

c)

cubical expansivity of container only

d)

superficial expansivity of container

293.

A liquid has an apparent cubic expansivity of 4 × 10⁻⁴ °C⁻¹ and the container has a cubic expansivity of 1 × 10⁻⁴ °C⁻¹. The real cubic expansivity of the liquid is

a)

1 × 10⁻⁴ °C⁻¹

b)

3 × 10⁻⁴ °C⁻¹

c)

4 × 10⁻⁴ °C⁻¹

d)

5 × 10⁻⁴ °C⁻¹

294.

Apparent expansion of liquids is best observed using

a)

a solid block

b)

a vacuum flask

c)

a glass container

d)

a metal rod

295.

A passenger standing in a moving bus suddenly falls forward when the bus stops abruptly. This is because:

a)

The passenger has greater mass than the bus

b)

The feet stop with the bus while the upper body continues moving

c)

The bus exerts a forward force

d)

Gravity increases suddenly

296.

Why is it easier to push a wheelbarrow than to carry the same load on your head?

a)

Less mass

b)

Friction is eliminated

c)

Wheel reduces effort by acting as a simple machine

d)

Gravity is reduced

297.

A car moving on a circular road is more likely to skid when:

a)

Speed is low

b)

Tyres are new

c)

Road is wet

d)

Radius is large

298.

Why do long jumpers bend their knees after landing?

a)

To reduce weight

b)

To increase time of impact

c)

To increase force

d)

To stop quickly

299.

A stone and a feather fall together in a vacuum. This shows that:

a)

Mass affects speed

b)

Air resistance affects falling bodies

c)

Gravity is absent

d)

Heavy objects fall faster

300.

Why does sweating cool the body?

a)

Sweat absorbs cold

b)

Sweat evaporates using body heat

c)

Sweat reduces blood flow

d)

Air cools the body

301.

Why are cooking pots made of metal but handles made of wood/plastic?

a)

Metal is lighter

b)

Wood is cheaper

c)

Metal conducts heat, handle should not

d)

Wood is stronger

302.

Why does water remain at 100°C while boiling?

a)

Heat is lost

b)

Temperature cannot increase

c)

Heat is used for phase change

d)

Thermometer error

303.

Why are desert nights cold despite hot days?

a)

No clouds to trap heat

b)

Sand absorbs cold

c)

Sun disappears

d)

Wind increases

304.

Why does a black surface feel hotter under sunlight than a white surface?

a)

Black reflects heat

b)

White absorbs heat

c)

Black absorbs more radiation

d)

White emits more

305.

Why does sound travel faster in solids than in air?

a)

Solids are heavier

b)

Molecules are closer

c)

Solids are louder

d)

Air resists sound

306.

Why can a person hear better underwater when two stones are struck?

a)

Sound is louder

b)

Water transmits sound efficiently

c)

Echo is reduced

d)

Frequency increases

307.

Why does a siren sound higher in pitch when approaching?

a)

Frequency increases due to Doppler effect

b)

Speed increases

c)

Amplitude increases

d)

Air pressure changes

308.

Why are soundproof rooms lined with soft materials?

a)

To increase sound

b)

To absorb sound waves

c)

To reflect sound

d)

To cool the room

309.

Why does a swimming pool appear shallower than it actually is?

a)

Reflection

b)

Refraction of light

c)

Absorption

d)

Diffraction

310.

Why is a mirage seen on a hot road?

a)

Reflection from road

b)

Refraction in layers of air

c)

Diffraction

d)

Absorption

311.

Why do stars appear to twinkle?

a)

Reflection

b)

Refraction in atmosphere

c)

Rotation

d)

Scattering

312.

Why are rear-view mirrors convex?

a)

To produce large images

b)

To widen field of view

c)

To invert image

d)

To reflect light more

313.

Why are electric cables covered with plastic?

a)

Decoration

b)

Insulation

c)

Increase current

d)

Reduce voltage

314.

Why do bulbs glow brighter in parallel than in series?

a)

More current flows

b)

Same voltage across each bulb

c)

Resistance increases

d)

Energy decreases

315.

Why does a fuse melt when current is high?

a)

Voltage increases

b)

Heat produced exceeds limit

c)

Resistance decreases

d)

Magnetic field increases

316.

Why is high voltage used for power transmission?

a)

Increase current

b)

Reduce power loss

c)

Increase resistance

d)

Reduce energy

317.

Why does a compass point North?

a)

Earth acts as magnet

b)

Sun attracts it

c)

Air current

d)

Gravity

318.

Why is soft iron used in electromagnets?

a)

Permanent magnet

b)

Easily magnetized and demagnetized

c)

Harder

d)

Cheaper

319.

Why do astronauts feel weightless in orbit?

a)

No gravity

b)

They are in free fall

c)

No mass

d)

Space pushes them

320.

Why is acceleration due to gravity less on mountains?

a)

Less air

b)

Distance from Earth’s center increases

c)

Temperature drops

d)

Pressure reduces

321.

Why do ships made of steel float?

a)

Steel is light

b)

Average density less than water

c)

No gravity

d)

Shape only

322.

Why do dams have thicker bases?

a)

Decoration

b)

Pressure increases with depth

c)

Strength only

d)

Weight increases

323.

Why are gamma rays dangerous?

a)

They are visible

b)

Highly penetrating

c)

Low energy

d)

Heavy

324.

Why are alpha particles least penetrating?

a)

High speed

b)

Large mass and charge

c)

No charge

d)

Low energy

325.

Why is efficiency never 100%?

a)

Work increases

b)

Friction causes energy loss

c)

Gravity changes

d)

Force reduces

326.

Why is a long spanner easier to use?

a)

More force

b)

Larger moment arm

c)

Less friction

d)

Smaller torque

327.

Why does a balloon expand when heated?

a)

Pressure increases outside

b)

Molecules move faster

c)

Mass increases

d)

Volume decreases

328.

Why does pressure increase when gas is compressed?

a)

Molecules collide more frequently

b)

Temperature decreases

c)

Volume increases

d)

Mass reduces

329.

Why is hydroelectric power preferred?

a)

Cheap only

b)

Renewable and clean

c)

Powerful only

d)

Easy only

330.

Why do airplanes take off against the wind?

a)

Reduce lift

b)

Increase lift

c)

Reduce speed

d)

Increase drag

331.

Why do cyclists bend forward when racing?

a)

Reduce weight

b)

Reduce air resistance

c)

Increase speed directly

d)

Increase friction

332.

Why does ice float on water?

a)

Heavier

b)

Lower density

c)

Higher pressure

d)

Lower temperature

333.

Why do glass windows crack when heated unevenly?

a)

Expansion differences

b)

Pressure

c)

Density change

d)

Mass increase

334.

Why do birds fluff their feathers in cold weather?

a)

Decoration

b)

Trap air (insulation)

c)

Increase weight

d)

Reduce motion

335.

Why does oil spread on water?

a)

Higher density

b)

Lower density

c)

Surface tension difference

d)

Gravity

336.

Why is lightning seen before thunder heard?

a)

Light faster than sound

b)

Sound louder

c)

Air blocks sound

d)

Distance changes

337.

Why do pressure cookers cook food faster?

a)

Less heat

b)

Higher pressure raises boiling point

c)

Less water

d)

Faster fire

338.

Why do objects appear smaller in convex mirrors?

a)

Reflection

b)

Diverging rays

c)

Refraction

d)

Absorption

339.

Why do metals expand more than glass?

a)

Lower density

b)

Stronger bonds

c)

Higher expansion coefficient

d)

Less heat

340.

Why does current decrease when resistance increases?

a)

Ohm’s law

b)

Energy loss

c)

Voltage drops

d)

Heat reduces

341.

Why is alternating current used in homes?

a)

Cheaper only

b)

Easily transformed

c)

Stronger

d)

Safe

342.

When resistance increases?

a)

Ohm’s law

b)

Energy loss

c)

Voltage drops

d)

Heat reduces

343.

Why is alternating current used in homes?

a)

Cheaper only

b)

Easily transformed

c)

Stronger

d)

Safer only

344.

Why do satellites not fall to Earth?

a)

No gravity

b)

Balanced by tangential velocity

c)

No mass

d)

Space force

345.

Why does a parachute slow down a falling object?

a)

Increase gravity

b)

Increase air resistance

c)

Reduce mass

d)

Reduce pressure

346.

Why is the sky blue?

a)

Reflection

b)

Scattering of light

c)

Refraction

d)

Absorption

347.

A heavy truck and a small car collide head-on. Which experiences greater force?

a)

Truck

b)

Car

c)

Both equal

d)

Depends on speed

348.

A ball thrown upward returns to the thrower. Ignoring air resistance, its speed just before hitting the hand is:

a)

Less

b)

Greater

c)

Same as initial

d)

Zero

349.

A body moving at constant velocity must have:

a)

Constant force

b)

Zero force

c)

Increasing force

d)

Decreasing force

350.

A stone tied to a string moves in a circle. If the string breaks, the stone moves:

a)

Radially outward

b)

In a circle

c)

Tangentially

d)

Backward

351.

A man jumps from a boat onto land. The boat moves backward because:

a)

Gravity

b)

Reaction force

c)

Friction

d)

Momentum loss

352.

Water at 0°C and ice at 0°C are mixed. Which is colder?

a)

Ice

b)

Water

c)

Same temperature

d)

Cannot tell

353.

A metal lid is loosened by heating because:

a)

Lid contracts

b)

Lid expands more than jar

c)

Jar expands more

d)

Pressure reduces

354.

Why does evaporation occur at all temperatures?

a)

Molecules have varying energies

b)

Heat is constant

c)

Air pressure zero

d)

Temperature fixed

355.

Increasing amplitude of a wave affects:

a)

Speed

b)

Frequency

c)

Energy

d)

Wavelength

356.

If frequency doubles, wavelength will:

a)

Double

b)

Halve

c)

Remain same

d)

Increase

357.

A sound cannot travel in space because:

a)

No gravity

b)

No medium

c)

Too cold

d)

No pressure

358.

An object is placed between focal point and convex lens. Image formed is:

a)

Real and inverted

b)

Virtual and upright

c)

Real and upright

d)

No image

359.

A plane mirror produces an image that is:

a)

Laterally inverted

b)

Vertically inverted

c)

Smaller

d)

Real

360.

A fish appears closer to the surface because:

a)

Reflection

b)

Refraction

c)

Absorption

d)

Diffraction

361.

Two identical bulbs connected in series glow dim because:

a)

Voltage shared

b)

Current increases

c)

Resistance decreases

d)

Power increases

362.

If resistance increases, current:

a)

Increases

b)

Decreases

c)

Constant

d)

Zero

363.

A wire gets hot when current flows because:

a)

Magnetic effect

b)

Heating effect

c)

Chemical effect

d)

Nuclear effect

364.

Breaking a magnet results in:

a)

Isolated poles

b)

Smaller magnets

c)

No magnetism

d)

Only north poles

365.

Magnetic field lines never intersect because:

a)

Weak field

b)

Direction becomes undefined

c)

No force

d)

Random motion

366.

A body weighs less at the equator because:

a)

Less mass

b)

Earth rotation reduces effective gravity

c)

No gravity

d)

Air pressure

367.

Mass is constant but weight changes because:

a)

Gravity varies

b)

Density changes

c)

Volume changes

d)

Pressure changes

368.

A block sinks because:

a)

Weight > upthrust

b)

Density high

c)

Pressure low

d)

Volume small

369.

Pressure at same depth in different liquids depends on:

a)

Density

b)

Area

c)

Volume

d)

Shape

370.

Beta particles are:

a)

Helium nuclei

b)

Electrons

c)

Protons

d)

Neutrons

371.

Radioactive decay is:

a)

Predictable per atom

b)

Random

c)

Linear

d)

Constant speed

372.

Mechanical advantage > 1 means:

a)

Effort greater

b)

Load greater

c)

Efficiency 100%

d)

No friction

373.

Increasing temperature at constant volume increases:

a)

Pressure

b)

Volume

c)

Density

d)

Mass

374.

Cooling a gas reduces pressure because:

a)

Molecules slow down

b)

Volume increases

c)

Mass decreases

d)

Density increases

375.

Energy cannot be created because of:

a)

Newton’s law

b)

Conservation law

c)

Gravity

d)

Motion

376.

Kinetic energy depends on:

a)

Speed squared

b)

Speed only

c)

Mass only

d)

Volume

377.

A cyclist stops pedaling but keeps moving due to:

a)

Friction

b)

Inertia

c)

Gravity

d)

Work

378.

A rocket moves forward because:

a)

Air pushes it

b)

Exhaust gases push backward

c)

Gravity pulls it

d)

Vacuum pulls

379.

Why does a glass break when suddenly cooled?

a)

Contraction stress

b)

Expansion

c)

Pressure

d)

Density

380.

Why is mercury used in thermometers?

a)

Low expansion

b)

High visibility & uniform expansion

c)

Cheap

d)

Low density

381.

Why do electric shocks occur?

a)

Voltage only

b)

Current through body

c)

Resistance

d)

Power

382.

Why do transformers not work with DC?

a)

No resistance

b)

No changing magnetic field

c)

High voltage

d)

Low current

383.

Why does oil reduce friction in machines?

a)

Increases force

b)

Forms thin layer

c)

Increases pressure

d)

Reduces mass

384.

Why is a sharp knife more effective?

a)

Less area → more pressure

b)

More mass

c)

Less force

d)

More friction

385.

Why do clouds appear white?

a)

Absorption

b)

Scattering of all wavelengths

c)

Reflection only

d)

Refraction

386.

Why do metals conduct electricity?

a)

Free electrons

b)

Strong bonds

c)

High density

d)

Low resistance

387.

Why does a parachutist reach terminal velocity?

a)

Gravity stops

b)

Air resistance equals weight

c)

Speed reduces

d)

Mass changes

388.

Why does a straw appear bent in water?

a)

Reflection

b)

Refraction

c)

Diffraction

d)

Absorption

389.

Why are transformers used in power supply?

a)

Store energy

b)

Change voltage

c)

Reduce current only

d)

Increase resistance

390.

Why do electrons flow in a conductor?

a)

Voltage difference

b)

Heat

c)

Pressure

d)

Mass

391.

Why does a body float better in salt water?

a)

Higher density → more upthrust

b)

Less gravity

c)

Lower pressure

d)

Less mass

392.

Why does sound reflect better on hard surfaces?

a)

Absorption low

b)

Density high

c)

Speed high

d)

Pressure high

393.

Why do lenses form images?

a)

Reflection

b)

Refraction of light

c)

Diffraction

d)

Absorption

394.

Why is nuclear energy powerful?

a)

Large mass conversion

b)

High temperature

c)

High pressure

d)

Fast reaction

395.

Why does a magnet lose strength when heated?

a)

Domains become disordered

b)

Charge lost

c)

Mass reduces

d)

Field increases

396.

Why does light slow down in glass?

a)

Interaction with atoms

b)

Reflection

c)

Absorption

d)

Diffraction