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WorksheetsYr2 Phyics
Total questions: 51
Worksheet time: 1hrs 14mins
The Earth may be assumed to be spherical with radius r and density p.
Which equation correctly relates the gravitational field strength g at its surface to these quantities and
the gravitational constant G?
g=G/ r2
g=3 G \ 4 π r p
g= G 4 π r p \ 3
g= G 4 π r2 p \ 3
The gravitational field strength outside a uniform sphere of mass Mis the same as that of a point mass Mat the centre of the sphere. The Earth, which may be assumed to be spherical and of radius r, has a gravitational field strength g at its surface. Which expression gives the gravitational field strength at height h above the ground?
g r2 / (r + h)2
g r / r + h
g (r- h) / r
g (r-h)2 / r2
What is the magnitude of the force between the two charged spheres shown? (Hint: You do not need to convert the units.)
1.6
1.4
1.2
1.0
A capacitor stores 100 mC of charge for every 0.33 kV of potential difference across its
plates. What is its capacitance?
0.30 mF
300 mF
3300 F
3.3 F
The acceleration of a bare helium nucleus in a uniform electric field of 0.6 V/mm would be:
1.15 x 10-10 m/s2
5.75 x 1010 m/s2
1.15 x 1011 m/s2
2.9 x 1010 m/s2
What is the electrostatic potential energy possessed by an electron 1.00 x 10-10 m from a proton in eV?
-12.7 eV
-3.70 x 10-37 eV
-14.4 eV
-11.4 eV
Determine the approximate maximum EMF generated by an a.c. generator if the magnetic flux through its 20 turn coil is as shown in the flux-time graph shown.
1200 V
120 V
60 V
6000 V
A -12 μC is located at x = 0 cm and a 3 μC charge at x = 4 cm. What is the strength of the electric field at location x = 6 cm, defining the positive x axis as positive?
+2.95 x 105 N/C
0
+3.75 x 107 N/C
-2.95 x 107 N/C
Determine the maximum weight a 20.0 m length of wire could possess in order for it to float in the Earth’s magnetic field per amp of current through it. Assume the Earth’s field is uniform and perfectly horizontal with a magnitude of 50.0 μT.
1.0 N/A
1.0 mN/A
0.1 mN/A
100 mN/A
Three identical capacitors are placed in series. When discharged through a 33 kΩ resistor they lose 95% of their charge in 90 ms. What value is each capacitance?
0.30 μF
2360 nF
0.024 mF
2.73 x 10-6 F
The two wires in the diagram have the currents indicated, both in the same direction, into the page. In the absence of any external magnetic fields they experience a force…
of repulsion from each other, the forces being equal and opposite
of attraction towards one another, the forces being equal and opposite
of repulsion from each other, the force on the 1 A wire being twice that of the 2 A wire
of attraction towards one other, the force on the 2 A wire being twice that of the 2 A wire
A simple circuit of a 12 V battery and 4 capacitors in parallel is made. The capacitors are identical in electrode area and material but the distance between their electrodes is different – this is shown in the data table.
If capacitor C1 has a capacitance of 3600 nF, how much energy is stored by the capacitance combination in the circuit?
0.54 mJ
540 nJ
450 μJ
0.045 mJ
A graph of ln (potential difference across capacitor) on the y-axis against time on the x-axis for the discharging curve of a capacitor, resistor with resistance R and a power supply of voltage V0 as shown would provide you with:
a gradient of 1/RC and an intercept of V0
a gradient of -1/RC and an intercept of V0
a gradient of -RC and an intercept of ln V0
a gradient of -1/RC and an intercept of ln V0
i) Uniform magnetic fields do not change the speed of charged particles within them.
ii) A uniform magnetic field applies no force on a stationary charge.
iii) Uniform electric fields apply a constant acceleration to a charged particle in the direction of the field.
Which of these statements is true?
Only i)
i) and ii)
i) and iii)
All three
What uniform magnetic flux density would need to be present in order to balance the force on a proton travelling at 3.5x106 m/s as it passes through parallel plate electrodes 4 cm apart with a potential difference of 20 kV between them i.e. so that the proton passes through in a straight line?
0.14 T
1.4 mT
7.0 T
7 mT
Different value capacitors in parallel, connected to a power supply, all possess the same…
Current through them
Charge on each one
Potential difference across each one
Electric field in each one
An a.c. generator is altered so that the EMF it produces is changed. It is given twice as many turns, rotated 25% slower, has the coil diameter increased by a factor of 1.25 and improved magnets installed with a field strength 1.5 times stronger than before.
What affect will this have on the EMF generated?
2.81 times higher amplitude, 25% lower frequency
4.69 times higher amplitude, 25% lower frequency
3.52 times higher amplitude, 25% lower frequency
2.81 times higher amplitude, 25% higher frequency
The base SI units for magnetic flux linkage are which of the following?
kgm2s-1C-1
kgms-2A-1
kgm-2s2A-1
kgm2s-2A-1
Choose the incorrect ending to the sentence. Transformers…
require an iron core to conduct the electricity from the primary to the secondary.
require that the core be laminated to reduce eddy currents.
require an a.c. input voltage to create a changing magnetic field.
multiply the voltage based on the ratio of the number of turns in the secondary coil to the primary coil.
An anti-proton is crossing the page from top to bottom. There is a uniform magnetic field coming out of the page towards you. In which direction will the anti-proton initially feel a force?
Directly into the page
To the right
To the left
Directly out of the page
The a.c. voltage from a household plug is 230 V. the power plant generates electricity at 25 kV and 1000 A, and the current transmitted along transmission lines is 62.5 A.
What must the turns ratio be for the step down transformer from the transmission lines to households. Assume any transformers involved are 100% efficient.
6.8 : 1
1740 : 1
109 : 1
1440 : 1
The distance between the Sun and Mars varies from 2.1 × 1011m to 2.5 × 1011m.
When Mars is closest to the Sun, the force of gravitational attraction between them is F.
What is the force of gravitational attraction between them when they are furthest apart?
0.71 F
0.84 F
1.2 F
1.4 F
A planet of mass M and radius R rotates so rapidly that loose material at the equator just remains on the surface. What is the period of rotation of the planet?
G is the universal gravitational constant.
A planet has a radius half the Earth’s radius and a mass a quarter of the Earth’s mass.
What is the approximate gravitational field strength on the surface of the planet?
1.6 N kg–1
5.0 N kg–1
10 N kg–1
20 N kg–1
Charon is a moon of Pluto that has a mass equal to that of Pluto.
The distance between the centre of Pluto and the centre of Charon is d.
X is the point at which the resultant gravitational field due to Pluto and Charon is zero.
What is the distance of Xfrom the centre of Pluto?
Which one of the following statements about gravitational potential is incorrect?
It is analogous to the electric potential at a point in an electric field.
It is equal to the gravitational potential energy of a mass of 1 kg.
It is a vector quantity.
The difference in gravitational potential between two points at different heights above the Earth depends on the position of the points.
Which graph shows how intensity I varies with angle θ when electrons are diffracted by a nucleus?
The radius of a uranium-238 nucleus is 7.75 × 10–15 m. What is the radius of a carbon-12 nucleus?
1.10 × 10–18 m
3.91 × 10–16 m
2.86 × 10–15 m
3.12 × 10–15 m
During a single fission event of uranium-235 in a nuclear reactor the total mass lost is 0.23 u. The reactor is 25% efficient.
How many events per second are required to generate 900 MW of power?
1.1 × 1014
6.6 × 1018
1.1 × 1020
4.4 × 1020
Which of the following substances can be used as a moderator in a nuclear reactor?
Boron
Concrete
Uranium-238
Water
Nobelium-259 has a half-life of 3500 s. What is the decay constant of nobelium-259?
8.7 × 10–5 s–1
2.0 × 10–4 s–1
1.7 × 10–2 s–1
1.2 × 10–2 s–1
A pure sample of nuclide X containing N nuclei has an activity A.
The half-life of X is 6000 years.
A pure sample of nuclide Y containing 3N nuclei has an activity 6A.
What is the half-life of nuclide Y?
1000 years
3000 years
12 000 years
18 000 years
β particles are emitted from a radioactive source in a school laboratory. What is correct for these particles?
A strong magnetic field will not deflect them.
They are absorbed by aluminium.
They do not damage human tissue.
Their range in air is shorter than that of α particles.
A radioactive source contains a nuclide which has a half-life of 12 hours. A detector placed near the source records an average count rate of 180 counts per minute. The average background count rate is 20 counts per minute.
What will be the average count rate after 24 hours?
40 counts per minute
45 counts per minute
50 counts per minute
60 counts per minute
Which graph best shows how the radius R of an atomic nucleus varies with the nucleon number A?
The diagram shows the path of an α particle deflected by the nucleus of an atom. Point P on the path is the point of closest approach of the α particle to the nucleus.
Which of the following statements about the α particle on this path is correct?
Its acceleration is zero at P.
Its kinetic energy is greatest at P.
Its potential energy is least at P.
Its speed is least at P.
Which of the following is equal to
1.19
1.25
1.33
1.40
In the reaction shown, a proton and a deuterium nucleus , fuse together to form a helium nucleus.
What is the value of Q, the energy released in this reaction?
mass of a proton = 1.00728 u
mass of a H-2 nucleus = 2.01355 u
mass of a He-3 nucleus = 3.01493 u
5.0 MeV
5.5 MeV
6.0 MeV
6.5 MeV
The mass of the beryllium-7 nucleus is 7.01473 u. What is the binding energy per nucleon of this nucleus?
Use the following data:
mass of proton = 1.00728 u
mass of neutron = 1.00867 u
1u = 931.3 MeV
1.6 MeV nucleon−1
5.4 MeV nucleon−1
9.4 MeV nucleon−1
12.5 MeV nucleon−1
Which one of the following statements is not true about the control rods used in a nuclear reactor?
They must absorb neutrons.
They must slow down neutrons to thermal speeds.
They must retain their shape at high temperatures.
The length of rod in the reactor must be variable.
The fusion of two deuterium nuclei produces a nuclide of helium plus a neutron and liberates 3.27 MeV of energy. How does the mass of the two deuterium nuclei compare with the combined mass of the helium nucleus and neutron?
It is 5.8 × 10−30 kg greater before fusion.
It is 5.8 × 10−30 kg greater after fusion.
It is 5.8 × 10−36 kg greater before fusion
It is 5.8 × 10−36 kg greater after fusion.
The actinium series of radioactive decays starts with an isotope of uranium, nucleon (mass) number 235, proton (atomic) number 92.
Which answer shows the nucleon number and proton number of the isotope after the emission of 5 α particles and 2 β– particles?
A=213 Z=82
A=215 Z=80
A=215 Z=84
A=227 Z=87
