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WorksheetsLIGHT,ELECTRICITY,MAGNETIC EFFECT REVISION
Total questions: 84
Worksheet time: 50mins
Choose the incorrect statement from the following regarding magnetic lines of field
The direction of magnetic field at a point is taken to be the direction in which the north pole of the compass needle points
Magnetic field lines are closed curves
If magnetic field lines are parallel and equidistant, they represent zero field strength
Relative strength of magnetic field is shown by degree of closeness of their field lines
Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand thumb rule to find the direction of the magnetic field outside the loop
Away from the table
Towards the table
Parallel to the table
The magnetic field inside a long current carrying solenoid
is zero
decreases as we move towards its end
increases as we move towards its end
is the same at all points
For a current carrying solenoid N- and S- poles are created at the two ends. Among the following statements, the incorrect statement is
The field lines inside the solenoid are in the form of straight lines which indicates that the magnetic field is the same at all points inside the solenoid
The strong magnetic field produced by the solenoid can be used to magnetise a piece of magnetic material like soft iron, when placed inside the coil
The pattern of the magnetic field associated with a solenoid is different from the pattern of magnetic field around a bar magnet
The N- and S- poles exchange position when the direction of current through the solenoid is reversed
A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in the figure. The direction of magnetic field at a point will be North to South
directly above the wire
directly below the wire
at a point located in the plane of the paper, on the north side of the wire
at a point located in the plane of the paper, on the south side of the wire
In 1820 oersted accidentally discovered:
Compass needle didn’t move when an electric current passed through a metallic wire placed nearby.
Compass needle got deflected when an electric current passed through a metallic wire placed nearby.
Compass needle moved when no electric current passed through a metallic wire placed nearby.
Metallic wire moved when compass was brought near it.
Why does a compass needle get deflected when brought near a bar magnet?
Bar magnet has electric current passing through it, therefore it deflects
Compass needle has electric current passing through it; therefore, it deflects when brought near a bar magnet
The magnetic field lines of the compass needle interact with the magnetic field lines of bar magnet, therefore it deflects
The north pole of the compass needle interacts with the north pole of the bar magnet, therefore it deflects
In a circuit if the current flows from north to south, the north pole of the compass needle would move towards?
North
West
East
South
If the direction of current is changed from north to south TO south to north, the direction of magnetic field is :
Reversed
Same
Perpendicular to wire
Perpendicular to previous direction of magnetic field
Magnetic field produced by a given current in the conductor ______ as the distance from it increases.
Decreases
Increases
Becomes zero
Remains the same
Which is the correct definition for current?
rate of flow of charge
energy per unit charge
reduces the flow of electrons
Voltmeters must be placed in...
parallel to the component being measured (to measure difference in energy)
series to the component being measured (to measure difference in energy)
parallel to the component being measured (to measure the number of electrons passing through it)
series to the component being measured (to measure the number of electrons passing through it)
An ammeter must be placed in...
series to measure the number of electrons passing through it
parallel to measure the number of electrons passing through it
series to measure the amount of energy passing through it
parallel to measure the number of electrons passing through it
Which of the following is the resistor symbol?
Select the ammeter and voltmeter circuit symbols from the following
Which of the following is the circuit symbol for a variable resistor?
An object is placed 20 cm in front of a plane mirror. The mirror is moved 2 cm towards the object. The distance between the positions of the original and final images seen in the mirror is:
2 cm
4 cm
10 cm
22 cm
A ray of light that strikes a plane mirror PQ at an angle of incidence of 30o, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is:
30°
45°
60°
90°
An object is placed at 100 mm in front of a concave mirror which produces an upright image (erect image). The radius of curvature of the mirror is:
Less than 100 mm
Between 100 mm and 200 mm
Exactly 200 mm
More than 200 mm
Which position of the object will produce a magnified virtual image, if a concave mirror of focal length 15 cm is being used?
10 cm
20 cm
30 cm
35 cm
A concave mirror produces a magnification of +4. The object is placed:
At the focus
Between focus and centre of curvature
Between focus and pole
Beyond the centre of curvature
A ray of light is travelling in a direction perpendicular to the boundary of a parallel glass slab. The ray of light:
Is refracted towards the normal
Is refracted away from the normal
Is reflected along the same path
Does not get refracted
A lens of focal length 12 cm forms an erect image, three times the size of the object. The distance between the object and image is:
8 cm
16 cm
24 cm
36 cm
The refractive index of four substances A, B, C and D are 1.31, 1.43, 1.33, 2.4 respectively. The speed of light is maximum in
(a) A
(b) B
(c) C
(d) D
If VB, VG, VR be the velocity of blue, green and red light respectively in a glass prism, then which of the following statement gives the correct relation?
(a) VB = VG = VR
(b) VB > VG >VR
(c) VB < VG < VR
(d) VB < VG > VR
The path of light is ______
(a) Rays
(b) Point
(c) Lines
(d) Beam
The velocity of light is _______
(a) 3x 10-8 ms-1
(b) 3 x 108 ms-1
(c) 3 x 108 km s-1
(d) 3 x 10-8 km s-1
Velocity and wavelength of light are related by a relation
(a) g-c⋋
(b) γ=cλγ=cλ
(c) c=γγ⋋
(d) Both b & c
If the energy of the incident and scattered beam of light are same, then it is called ______ scattering
(a) Ray light
(b) Inelastic
(c) Mie
(d) Elastic
10. The scattering of light by colloidal particles is _____ scattering.
(a) Ray light
(b) Mie
(c) Raman
(d) Tyndall
f=R/2 is valid for
convex mirror only not for concave mirror
concave mirror only not for convex mirror
both concave and convex mirror
neither for concave nor for convex
A ray parallel to the principal axis is incident on a concave mirror. The reflected ray will
pass through the focus
pass through the centre of curvature
pass through the pole
retrace its path
To get an image larger than the object, one can use
convex mirror but not concave mirror
concave mirror but not convex mirror
both mirror
neither convex nor concave
To obtain an image of same size as that of the object, one should use ____________________mirror and object should be placed at________________
convex , C
concave , C
convex, F
concave, between p and F
The magnification m of an image formed by a mirror is negative. it means, the image is
smaller than the object
larger than the object
erect
inverted
An object is placed at the centre of curvature of a concave mirror. the distance between the image and the pole is
equal to f
equal to 2f
between f and 2f
greater than 2f
If an incident ray passes through the center of curvature of a spherical mirror, the reflected ray
passes through the focus
passes through the pole
retrace its path
will go parallel to the principal axis
The magnification of an image formed by a spherical mirror is m = +1.5, It means the image is
inverted and bigger than the object
erect and smaller in size
inverted and smaller in size
erect and enlarged
To get an erect, virtual and magnified image formed by a convex lens the object should be placed
between O and F
between F and 2F
beyond 2F
at 2F
A concave lens forms ________ , ________and _______image
real, inverted and enlarged
virtual, erect and of same size
virtual, erect and magnified
virtual, erect and diminished
A convex lens forms image of same size when the object is placed
at F
between O and F
at 2F
between F and 2F
A ray of light incident obliquely from water (1.33) to glass (1.52) will
bend away from the normal
go undeviated
bend towards the normal
retrace its path
Which of the following relations between various angles is true for refraction of light through a rectangular glass slab?
i = r = e
i > r and i is not equal to e
i < r and i = e
r < i and i = e
The power of a lens is +5D. It is a
concave lens of focal length 20 cm
concave lens of focal length 5 cm
convex lens of focal length 20cm
convex lens of focal length 5 cm
An object is placed at a distance of 20cm from a convex lens of focal length 10cm. The image will be formed
at 10cm from the lens on the other side
at 20cm from the lens on the other side
at 10cm from the lens on the same side
at 10cm from the lens on the same side
Why does light refract?
speeds up
gets hot
slows down
gains energy
WHICH DEVICE IS USED FOR MEASURING SMALL CURRENT ?
VOLTMETER
DOUBLE AMMETER {SPECIFIC}
GALVANOMETER
AMMETER
WHICH OF THIS IS GOOD CONDUCTOR OF ELECTRICITY?
AMMETER
VOLTMETER
BOTH A AND B
NON OF THESE
WHICH GAS PREVENTS TUNGSTEN PRESENT IN THE BULB TO BE OXIDISED?
HYDROGEN GAS
NITROGEN
ARGON
ALL OF THE ABOVE
THE COMMERCIAL UNIT OF ELECTRIC ENERGY IS
(a)
The equivalent resistance of the series combination of two equal resistances is S. When they are joined in parallel, the total resistance is “P”. If S = nP, what is the value of “n”?
2
1
4
3
6
The resultant value of resistances each of value r ohms when connected in parallel is x, when these resistances are connected in series the resultant resistance is : (HOTS)
(x/n)2
N^2X
nx
(x/n)
According to ohms law,
The resistance increases with the increases in current.
The resistance increases with the increases in voltage.
The resistance and current both increases wiTh the increases in voltage.
The current increases with the increases in voltage.
Electrical potential is ------------
scalar quantity
vector quantity
both scalar and vector
neither scalar nor vector
kilowatt hour is unit of
energy
power
momentum
force
SI unit of resistivity (specific resistance) is ----------
ohm
ohm meter
volt
ampere
How is a voltmeter connected in the circuit to measure the potential difference between two points?
series
parallel
according to the situation either series or parallel
none
SI unit of electric current is -----------
volt
coulomb
ampere
ohm
SI unit of resistance is ------------
ohm
volt
ampere
coulomb
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, power consumed will be ---------------. [Use P = (V X V)/R]
100 W
75 W
50 W
25 W
The property of a conductor by which it obstructs the flow of current is known as ------------------ of the conductor
voltage
conductivity
power
resistance
What is the direction of conventional current?
positive terminal to negative terminal
negative terminal to positive terminal
depends on the condition
none
Ammeter is used to measure ----------------.
voltage
electric current
resistance
resistivity
Ohm's law is applicable only when ----------------
temperature remains constant
temperature increases
temperature decreases
none
Keeping the potential difference constant, the resistance of the circuit is halved, the current will become --------------
four times
half
double
one-third
Electrical resistivity of a given metallic wire depends upon ----------
its length
its thickness
its shape
nature of the material
What is the SI unit of electric charge?
ampere
volt
ohm
coulomb
What is the maximum resistance which can be made using five resistor each of 1/5 ohm?
1/5 ohm
10 ohm
5 ohm
1 ohm
What is the minimum resistance which can be made using five resistors each of 1/5 ohm?
1/5 ohm
1/25 ohm
1/10 ohm
1/25 ohm
When a 4 ohm resistor is connected across the terminals of a 2 V battery, the number of coulombs passing through the resistor per second is --------------
0.5
1
2
4
If the current flowing through a fixed resistor is halved, the heat produced in it will become -----------------
one-fourth
one-half
double
four times
The solution which conducts electricity is known as --------
conductor
electrolyte
insulator
none
The work done to bring unit positive charge from infinity to a point in an electric field is known as ----------
potential
resistance
current
charge
An electric iron of resistance 20 ohm takes a current of 5 A. Calculate the heat developed in 30 s. [Use H = I X I X R X t]
1000 joules
2000 joules
15000 joules
30000 joules
An electric iron of resistance 20 ohm takes a current of 5 A. Calculate the heat developed in 30 s. [Use H = I X I X R X t]
1000 joules
2000 joules
15000 joules
30000 joules
Calculate resistance of an electric bulb which allows a 10 A current when connected to 220 V power source. [Use V = IR]
10 ohm
12 ohm
22 ohm
32 ohm
When a 12 V battery is connected across an unknown resistor, there is a current 2.5 mA in the circuit. Find the value of resistance of the resistor. [Use V = IR]
1000 ohm
2000 ohm
4800 ohm
6700 ohm
