Questions 1
(a) Topic – 1.c
(b) Topic- 1.c
A pencil has a weight of 0.16N.
(a) What is the mass of the pencil?
A 1.6g
B 16g
C 160g
D 1600g
(b) The diagram shows the pencil with one end resting on a small block.
A finger provides an upwards force, F, to keep the pencil horizontal.
(i) The weight of the pencil is 0.16N. Calculate the moment of the weight of the pencil about the pivot. Use the formula
moment = force × perpendicular distance from the pivot
(ii) State the moment of the force F.
(iii) Show that force F is 0.080N.
▶️Answer/Explanation
Ans
(a) B – 16 g;
A cannot be correct as g on Earth is not 100
C cannot be correct as g on Earth is not 1
D cannot be correct as g on Earth is not 0.1
(b) (i) substitution into given formula;
correct evaluation;
correct answer: 0.59(2) (N cm)
e.g.
moment = 0.16 × 3.7
moment = 0.592 (N cm)
(ii) 0.59(2) (N cm);
(iii) substitution;
re-arrangement and evaluation;
e.g.
0.592 = F × 7.4
F = 0.592 ÷ 7.4 = 0.08(0)
Questions 2
(a) Topic – 4.c
(b) Topic- 4.c
A solid bar of chocolate is taken from a refrigerator.
(a) The temperature of the chocolate bar is 5°C. Describe the arrangement and motion of the particles inside the chocolate bar.
(b) The chocolate is heated at a constant rate until the temperature reaches 45°C. The chocolate has a melting point of 32°C and a boiling point of 55°C.
(i) Describe the motion of the particles in the chocolate when the chocolate is at a temperature of 45°C.
(ii) Which of these is used to measure the temperature of the chocolate?
A balance
B ruler
C stopwatch
D thermometer
(iii) Use the axes to sketch a graph of how the temperature of the chocolate changes with time when it is heated from 5°C to 45°C.
▶️Answer/Explanation
Ans
(a) arrangement:
fixed (position) / eq;
motion:
vibrating /eq ;
(b) (i) (movement now) random;
idea that particles are no longer in fixed position;
(ii) D – thermometer;
A cannot be the answer as a balance measures mass
B cannot be the answer as a ruler measures length
C cannot be the answer as a stopwatch measures time
(iii) temperature increases from 5 °C to 45 °C;
temperature remains constant at some stage below 45 degrees;
single constant temperature section at 32 °C;
Questions 3
(a) Topic – 3.c
(b) Topic- 9.b
(c) Topic-9.b
The diagram shows the inside of an oscilloscope. Electrons leave the electron supply and accelerate towards the screen. The stream of electrons hits the screen.
(a) The grid is connected to the positive terminal of a high voltage power supply.
(i) Explain, in terms of the movement of particles, how the grid has become positively charged.
(ii) State the formula linking kinetic energy, mass and speed.
(iii) Calculate the speed of an electron when it has \(1.3 \times 10^{–15} J\) of kinetic energy. The mass of an electron is \(9.1 \times 10^{–31} kg\).
(b) The stream of electrons spreads out as it travels towards the screen. Explain why the electrons in the stream move apart from each other.
(c) The oscilloscope can cause the electrons to move in a circle. This produces a circular pattern on the screen.
(i) Use the scale to determine the radius of the circle.
(ii) The time taken for the electrons to complete one orbit of the circle is 24 ms. Calculate the orbital speed of the electrons. Use the formula
\(orbital \ speed=\frac{2 \pi \times orbital \ radius}{time \ period}\)
▶️Answer/Explanation
Ans
(a) (i) idea of transfer of electrons (from grid);
grid has lost electrons;
(ii) \(KE = \frac{1}{2} m v^2\)
(iii) substitution in correct formula;
re-arrangement;
correct evaluation;
correct answer: \(5.3 × 10^7 (m/s)\)
e.g.
\(1.3 \times 10^{−15} = \frac{1}{2} × 9.1 \times 10^{−31} \times v^2\)
\(v^2 = 2.857… \times 10^{15}\)
\(v = 5.345… \times 10^7(m/s)\)
(b) idea that electrons are (all) negatively charged/like charged;
like charges repel;
(c) (i) 2.5 (cm);
(ii) substitution into given formula;
conversion of ms to s and cm to m;
correct evaluation using radius;
correct answer: 6.5 (m/s)
e.g.
orbital speed = 2 π r ÷ T
orbital speed = \(2 π \times 2.5 \times 10^{−2}÷ (24 \times 10^{−3})\)
orbital speed = 6.544… m/s
Questions 4
(a) Topic – 1.c
(b) Topic-1.c
(c) Topic-1.c
(d) Topic- 1.b
The diagram shows two birds, just before bird X catches the smaller bird Y. Both birds are travelling horizontally at constant velocity.
(a) Show that the momentum of bird X is about 5kgm/s.
(b) The momentum of bird Y just before it is caught is 0.15kgm/s. Calculate the total momentum of the birds just before bird X catches bird Y.
(c) State the total momentum of the birds just after bird X has caught bird Y.
(d) Bird Y has a mass of 0.17kg. Calculate the velocity of the birds just after bird X has caught bird Y.
▶️Answer/Explanation
Ans
(a) 0.41 × 13;
5.3(3);
(b) 5.15 / 5.45 / 5.48 / 5.5;
(c) same as candidate’s answer to (b)
i.e. 5.48 (kg m/s);
(d) total mass = 0.58 (kg);
substitution of candidate’s answer to part (c);
rearrangement and correct evaluation;
correct answer: 9.4 (m/s)
e.g. total momentum = 5.48 kg m/s
total mass = 0.58 kg
velocity = 5.48 ÷ 0.58
velocity = 9.448… (m/s)
Questions 5
(a) Topic – 8.c
(b) Topic-8.c
(c) Topic-8.c
(d) Topic-8.c
The diagram shows some of the components of a nuclear fission reactor.
(a) Describe how a chain reaction occurs in a nuclear fission reactor.
(b) Describe the role of the control rods in a nuclear fission reactor.
(c) Describe how the process of nuclear fission is different from the process of nuclear fusion.
(d) (i) Which of these is the name of the nuclear process that is the main energy source for stars?
A alpha decay
B fission
C fusion
D gamma decay
(ii) Give a reason why the nuclear process in stars does not happen at low temperatures and pressures.
▶️Answer/Explanation
Ans
(a) (uranium) initial nucleus absorbs a neutron /eq ;
(uranium) nucleus splits/fission releasing (further) neutron(s);
idea of neutrons can be absorbed by or can cause further fissions with other (uranium) nuclei
(b) any TWO from:
absorb neutron(s);
idea of preventing them from causing fission;
idea of slowing rate of fission;
(c) fission is the splitting of a nucleus;
fusion is the combining of nuclei;
(d) (i) C – fusion;
A cannot be correct as there are very few nuclei with Z > 82;
B cannot be correct as there are very few nuclei with A > 56;
D cannot be correct as fusion is required to produce excited nuclei
(ii) idea of (electrostatic) repulsion of nuclei or protons (prevents fusion);
Questions 6
(a) Topic – 2.b
(b) Topic- 2.b
The National Grid is used in the United Kingdom for the large-scale transmission of electricity. The photograph shows solar panels connected to the National Grid.
(a) Solar panels provide direct current to a device that outputs an alternating current so that the energy from the solar panels can be supplied to the National Grid.
(i) Explain why a step-up transformer is used to supply the National Grid.
(ii) This is the label on the step-up transformer.
State the formula linking input voltage, output voltage and turns ratio for a transformer.
(iii) Calculate the number of turns on the secondary coil of the step-up transformer.
(b) Solar panels produce constant direct current (d.c.). Explain why a transformer will not work when connected to constant direct current.
▶️Answer/Explanation
Ans
(a) (i) (stepping up voltage) reduces current;
reducing current reduces heating in the wire;
(ii) \((N_p ÷ N_s) = (V_p ÷ V_s)\)
(iii) substitution;
re-arrangement;
correct evaluation;
correct answer: 32 000
\((N_p ÷ N_s) = (V_p ÷ V_s)\)
\((1400 ÷ N_s) = (15 ÷ 340)\)
\(N_s = (340 ÷ 15) × 1400\)
\(N_s = 31 733\)
(b) constant current gives constant magnetic field;
induction (in transformers) requires a changing magnetic field;
no voltage will be induced;
Questions 7
(a) Topic – 5.d
(b) Topic- 9.d
(a) A glass prism can be used to refract light.
(i) State the name of the piece of equipment used to measure angles.
(ii) Measure the angle of incidence and the angle of refraction for the light entering the prism.
(iii) State the formula linking refractive index, angle of incidence and angle of refraction.
(iv) Calculate the refractive index of the glass.
(b) Two galaxies, A and B, emit red light with a reference wavelength of 630nm. An astronomer measures the wavelength of red light from galaxy A when the light arrives at the Earth. The astronomer’s value for the wavelength is 645nm.
(i) Calculate the difference between the astronomer’s value for the wavelength and the reference wavelength of red light.
(ii) The change in wavelength happens because galaxy A is moving away from the Earth. Calculate the speed of galaxy A.
[speed of light = \(3.0 × 10^8 m/s\)]
(iii) Light from galaxy B has twice the redshift as light from galaxy A. Galaxy B is twice as far away from Earth as galaxy A. Explain how these observations support the Big Bang theory of the origin of the Universe.
▶️Answer/Explanation
Ans
(a) (i) protractor;
(ii) angle of incidence between 42 and 46 degrees;
angle of refraction between 26 and 30 degrees;
(iii) refractive index = sin(angle of incidence) ÷ sin(angle of refraction)
(iv) substitution;
correct evaluation;
correct answer: 1.5
e.g.
n = sin(i) ÷ sin(r)
n = sin() ÷ sin() = 1.479…
(b) (i) 15 (nm);
(ii) substitution into given formula;
re-arrangement;
correct evaluation;
correct answer: 7 100 000 (m/s)
e.g.
Δλ ÷ λ = v/c
\(15 ÷ 630 = v ÷ (3.0 × 10^8)\)
\(v = (3.0 × 10^8) × (15 ÷ 630)\)
\(v = 7.14 × 10^6 (m/s)\)
(iii) link between twice the redshift and twice the speed;
PLUS one from:
link between larger speed and larger distance;
(which in turn means that) galaxies are moving apart /moving away from each other;
Questions 8
(a) Topic – 4.c
(b) Topic- 4.c
Concrete on top of buildings can be used to heat water. The photograph shows a concrete and water heating system being built into the roof of a house.
(a) A scientist wants to determine the specific heat capacity of concrete. The diagram shows some of the equipment they could use. 
Describe a suitable method to find the specific heat capacity of concrete.
(b) Explain the advantage of the concrete having a high specific heat capacity when it is used to heat water in the heating system.
▶️Answer/Explanation
Ans
(a) Any FIVE from:
MP1 mass found on balance;
MP2 time measured on timer/stopwatch/stopclock;
MP3 temperature change = final temp – initial temp;
MP4 energy supplied = voltmeter reading × ammeter reading × time;
MP5 rearrangement of formula sheet equation;
i.e. c = energy supplied/(m × temp change)
MP6 keep taking temperature after heater switched off for max temp;
MP7 plot a graph of temperature against time;
MP8 find gradient of temperature-time graph;
MP9 use of “equation gradient = power of heater/ m x c” or re-arrangement;
MP10 (whole experiment) repeated and averaged;
(b) concrete can store/absorb/release a lot of energy (because of high SHC);
water temp maintained for longer/ temp rise for water more than temp drop for concrete;