Questions 1
The photograph shows a person using a roll of plastic wrapping to cover a plate of food. The plastic wrapping sticks to the plate due to electrostatic charges.
The passage explains why the plastic wrapping sticks to the plate. Use words from the box to complete the passage. Each word may be used once, more than once, or not at all. 
The person pulls a layer of plastic wrapping from the roll.
Forces between the layers of wrapping transfer particles called …………………………………………………….. from one layer to another layer.
The layer gaining these particles acquires a …………………………………………………….. charge.
The layer losing these particles acquires a …………………………………………………….. charge.
The negatively charged layer of wrapping repels …………………………………………………….. in the plate, leaving a positive charge in the plate where it touches the plastic wrapping.
The wrapping and plate …………………………………………………….. due to them having opposite charges.
▶️Answer/Explanation
Ans
electrons;
negative;
positive;
electrons;
attract;
Questions 2
The photograph shows an ice cube placed on a metal tile. The solid ice cube melts to become liquid water.
(a) Compare the arrangement of particles in a solid with the arrangement of particles in a liquid. You may draw a diagram to help your answer.
(b) Describe the difference in the movement of particles in a solid compared with the movement of particles in a liquid.
(c) After the ice cube has melted, the liquid water increases in temperature. The water has a mass of 16g and a specific heat capacity of 4200J/kg°C. Calculate the energy transferred to the liquid water as it increases in temperature from 3°C to 21°C.
▶️Answer/Explanation
Ans
(a) particles in a solid have a regular arrangement;
particles in a liquid have an irregular arrangement;
particles in both are closely packed;
(b) particles vibrate (about fixed positions) in a solid;
idea that particles move around in a liquid/eq;
(c) evaluation of temperature change;
substitution into ∆Q = m × c × ∆T;
evaluation;
e.g.
∆T = (21 – 3) = 18 (°C)
∆Q = 0.016 × 4200 × 18
(∆Q =) 1200 (J)
Questions 3
Kori Nuclear Power Plant in South Korea is one of the world’s largest nuclear fission power stations.
(a) The reactors at Kori use nuclear fission to generate electricity. The products released during nuclear fission have high energy in their kinetic store. Give a product of nuclear fission.
(b) Give two disadvantages of using nuclear fission to generate electricity.
(c) Kori has a maximum power output of \(7.49 × 10^9W\).
(i) State what is meant by the term power.
(ii) Calculate the minimum time taken for Kori to transfer \(6.47×10^{14} J\) of energy.
▶️Answer/Explanation
Ans
(a) daughter nuclei / named nuclei e.g. krypton or barium/ neutron(s);
(b) any two from:
MP1. radioactive waste;
MP2. uranium is radioactive;
MP3. non-renewable;
MP4. risk of nuclear accident/eq;
MP5. higher {setup / decommissioning} cost;
(c) (i) rate of {energy transfer/doing work};
(ii) substitution into P = W / t;
rearrangement;
evaluation; -1 for POT error
e.g.
\(7.49 × 10^9 = 6.47 × 10^{14} / t\)
\(t = 6.47 × 10^{14} / 7.49 × 10^9\)
(t =) 86 400 (s)
Questions 4
A squash ball is made of rubber and used to play a game called squash.
A student observes that the squash ball bounces higher after its temperature increases. The student designs an investigation to see how the temperature of the ball affectsthe maximum height after it bounces.
(a) State the independent and dependent variables in the student’s investigation.
(b) The diagram shows the ball at its maximum height after it bounces. Determine the distance the ball moves from the floor to its maximum height. Assume the ball does not change shape when it bounces.
[1cm on diagram = 4cm in laboratory]
(c) Design a method that the student could use to investigate how the temperature of the ball affects the maximum height after it bounces. Your answer should include details of
• apparatus needed
• measurements required
• control variables
You may draw a diagram to support your answer.
▶️Answer/Explanation
Ans
(a) IV = temperature (of ball);
DV = height (of bounce);
(b) measurement from floor to bottom of ball;
correct use of scale;
e.g.
distance = 6.2 (cm)
distance = (6.2 × 4 =) 24.8 (cm)
(c) six marks as distributed:
apparatus (2 marks max.)
MP1. ruler / tape measure;
MP2. idea of water bath (and thermometer);
measurements (2 marks max.)
MP3. range of temperatures;
MP4. height of the ball’s (first) bounce;
MP5. height measured at eye level;
MP6. repeats taken at each temperature and mean found;
control variables (2 marks max.)
MP7. height ball is dropped from;
MP8. surface the ball bounces on;
MP9. condition of drop;
MP10. idea of using multiple copies of the same ball;
Questions 5
Diagram 1 shows a wooden plank balanced horizontally on two supports, A and B. A block is suspended from the plank between the supports by a cable of negligible weight.
(a) The weight of the block is 260N.
(i) State the formula linking moment, force and perpendicular distance from the pivot.
(ii) By taking moments about support A, calculate force F. Assume the weight of the plank is negligible.
(iii) Explain what will happen to the magnitude of force F if the block is moved towards support B.
(b) Diagram 2 shows the block and the cable connecting the block to the plank.
(i) The centre of gravity of the block is located at point X. Draw an arrow on diagram 2 to show the weight of the block.
(ii) The block also experiences a force due to the tension in the cable. Explain why the block remains stationary when it is supported by this tension force.
(iii) Explain why the forces acting on the block are not an example of Newton’s third law of motion.
▶️Answer/Explanation
Ans
(a) (i) moment = force × (perpendicular) distance;
(ii) correct calculation of or substitution for moment of block’s weight;
use of principle of moments;
evaluation of force F;
e.g.
(moment of weight = 260 × 0.25 =) 65 (Nm)
65 = force F × 0.80
force F = 81 (N)
(iii) force F increases;
with any two from:
* distance from support A increases / distance from support B decreases;
* clockwise moment / moment of weight increases;
* anti-clockwise moment / moment of force F increases (to keep balance);
(b) (i) one vertical downwards arrow drawn;
arrow starts at centre of gravity;
(ii) any two from:
MP1. tension force is upwards;
MP2. tension force is same magnitude as weight / eq;
MP3. idea of no resultant force / acceleration;
(iii) any two from:
MP1. forces are acting on the same body;
MP2. idea that forces are not the same type / origin;
MP3. correct example of Newton’s third law pair;
Questions 6
This question is about magnetic fields.
(a) A student positions a thick wire vertically through the centre of a horizontal card. The student then passes a constant current through the wire in the downward direction, as shown in diagram 1.
(i) On diagram 1, draw the shape and direction of the magnetic field produced by the current in the wire.
(ii) Describe a method the student could use to show the shape of the magnetic field produced by the current in the wire.
(b) The student then removes the card and sets up a second wire next to the first wire, as shown in diagram 2.
The current in both wires is in the downward direction. The student observes that the wires move towards each other. Explain why the wires move towards each other.
▶️Answer/Explanation
Ans
(a) (i) single circle centred on the wire and parallel to the plane of the card;
at least two concentric circles in the same plane;
clockwise direction arrow marked on at least one line;
e.g.
(ii)
EITHER:
MP1. iron filings (used);
MP2. tap card / eq.;
OR
MP1. (plotting) compass (used);
MP2. multiple compasses used / compass moved to new position;
(b) any three from:
MP1. (both) wire(s) have magnetic fields around them;
MP2. each wire has a current in a magnetic field;
MP3. each wire experiences a force;
MP4. forces are same size but in opposite directions;
OR
MP1. RH grip rule indicates relationship between current and field for one of the wires;
MP2. LH rule indicates relationship between field from one wire, current in other wire and force on second wire;
MP3. combination of these two will give force on second wire towards first wire;
Questions 7
A student uses this method to investigate the speed of sound in air.
• set up an oscilloscope to detect and display a sound wave
• use a computer and a speaker to produce a sound of known wavelength
• use the oscilloscope to determine the frequency of the sound wave
• use a formula to calculate the speed of sound
(a) Give the name of the equipment that should be connected to the oscilloscope to detect the sound wave.
(b) The diagram shows the oscilloscope screen and the oscilloscope settings.
(i) Determine the frequency of the sound wave.
(ii) The wavelength of the sound wave is 27cm. Calculate the speed of sound.
(iii) Describe how the oscilloscope could be adjusted to show fewer wave cycles on the screen.
▶️Answer/Explanation
Ans
(a) microphone;
(b) (i) determination of number of squares for 1 period by finding average period from whole diagram;
correct use of timebase of 0.5 ms seen;
evaluation of time period;
evaluation of frequency;
e.g.
1 period = 8 squares ÷ 5 = 1.6 squares
time period = \(1.6 × 0.5(×10^{-3})\)
time period = \(8.0×10^{-4} s\)
frequency = \((1/8.0×10^{-4})\) = 1250 (Hz)
(ii) use of speed = frequency × wavelength;
dimensionally correct substitution;
evaluation;
e.g.
speed = frequency × wavelength
speed = 1250 × 0.27
(speed =) 340 (m/s)
(iii) idea of adjusting timebase;
idea of decreasing timebase/eq;
Questions 8
A binary star system has two nearby stars, which orbit each other in a circular path around a common centre of gravity.
(a) In an eclipsing binary system, one star passes behind the other star in its orbit. This causes a decrease in the light intensity of the binary star system when viewed from Earth. The graph shows how the light intensity of the binary star system changes with time. 
(i) Suggest why the decreases in light intensity are not all the same.
(ii) Use the graph to determine the time period of the binary star system.
(iii) One of the stars in this binary system has an orbital speed of 19km/s. Calculate the orbital radius of this star.
(b) A different binary star system is in a distant galaxy. When observed from the Earth, light from this galaxy has a longer wavelength than the wavelength of the light when it is emitted from the galaxy. Explain why this gives evidence for the Big Bang theory.
▶️Answer/Explanation
Ans
(a) (i) idea that stars are not the same size / mass / brightness /
(absolute) magnitude/ luminosity /temperature /depends
on which star is in front;
(ii) any answer that rounds to 31 (years);
(iii) conversion from years to seconds;
substitution;
rearrangement;
evaluation;
e.g.
31 years = \(9.78 × 10^8\) seconds
19 = 2π × radius / \(9.78 × 10^8\)
(radius =) 19 × \(9.78 × 10^8\) / 2π
(radius =) \(3.0 × 10^9\) (km)
(b) any three from:
MP1. light (from galaxy) has been red-shifted;
MP2. {binary system / galaxy} is moving away (from Earth);
MP3. universe is expanding;
MP4. (therefore) universe must have been at a single point some time in the past;