Questions 1
(a) Topic – 1.c
(b) Topic- 1.c
(a) The boxes show some physical quantities and their units. Draw a straight line from each physical quantity to its correct unit. One has been done for you.
(b) Some physical quantities are scalars and other physical quantities are vectors.
(i) State the difference between a scalar quantity and a vector quantity.
(ii) Give an example of a scalar quantity.
▶️Answer/Explanation
Ans
(a)
(b) (i) idea that vectors have a direction but scalars do not;
(ii) any correct scalar;
Questions 2
(a) Topic – 3.d
(b) Topic- 3.d
This question is about different methods of generating electricity.
(a) Natural gas can be burned to generate electricity. Name the energy store that decreases when natural gas is burned.
(b) Burning natural gas and the movement of water waves can both be used to generate electricity. Discuss the advantages and disadvantages of these two methods of generating electricity.
▶️Answer/Explanation
Ans
(a) chemical (energy store);
(b) any one advantage of natural gas from:
MP1. idea that electricity generated can change to meet demand;
MP2. idea that it is reliable;
any one disadvantage of natural gas from:
MP3. non-renewable / gas will eventually run out;
MP4. burning gas produces \(CO_2\) and greenhouse gases;
MP5. dependency on other countries to supply gas;
any one advantage of wave power from:
MP6. idea that it is renewable;
MP7. produces no polluting gases;
any one disadvantage of wave power from:
MP8. idea that waves might not always be present;
MP9. (may) cause harm to wildlife;
MP10. possible storm damage to the generator;
Questions 3
(a) Topic – 2.c
(b) Topic-2.c
A cleaning product is applied to a car using a sponge pad. The sponge pad is rubbed against the car to apply the cleaning product.
(a) Some parts of the car are made of metal and other parts are made of plastic. The metal parts of the car are earthed. Explain why the pad becomes charged when rubbing the plastic parts, but not when rubbing the metal parts.
(b) The sponge pad is held near a metal post that is connected to the ground. The sponge pad discharges with a small spark through the air to the metal post.
(i) The sponge pad stores 5.0mJ of energy in its electrostatic store. The voltage between the sponge pad and the metal post is 6000V. Calculate the charge transferred by the spark.
(ii) The small spark between the sponge pad and the metal post demonstrates that the sponge pad is charged. Describe a different experiment that could demonstrate that the sponge pad is charged. You may draw a diagram to support your answer.
▶️Answer/Explanation
Ans
(a) any three from:
MP1. idea that plastic is an insulator OR that metal is a conductor;
MP2. idea that charge/electrons are transferred (by rubbing/friction);
MP3. charge/electrons remain/build up on plastic parts;
MP4. charge/electrons flow through the metal parts/travel to earth;
(b) (i) substitution into energy = charge × voltage;
rearrangement;
evaluation;
e.g.
(0.00)5 = charge × 6000
charge = (0.00)5 / 6000
(charge =) \(8.3 × 10^{−7} (C)\)
(ii) idea of bringing pad near another uncharged insulator;
attraction used to demonstrate charge on sponge;
Questions 4
(a) Topic – 1.c
(b) Topic- 1.c
(c) Topic- 1.c
The photograph shows a dummy during a test of the safety features of a car in a collision.
Before the collision, the dummy in the car is travelling at a velocity of 14m/s. The dummy has a momentum of 1100kgm/s.
(a) (i) State the formula linking momentum, mass and velocity.
(ii) Show that the mass of the dummy is approximately 80kg.
(b) The dummy is brought to rest during the collision by a mean force of 15kN. Calculate the time taken for the dummy to be brought to rest in the collision.
(c) The car being tested is fitted with airbags. Using ideas about momentum, explain how an airbag reduces the force experienced by the dummy in the collision.
▶️Answer/Explanation
Ans
(a) (i) momentum = mass × velocity;
(ii) substitution;
rearrangement;
evaluation to 2 or more s.f.;
e.g.
1100 = mass × 14
mass = 1100 / 14
(mass =) 79 (kg)
(b) substitution into F = ∆p / t;
rearrangement;
evaluation;
e.g. 15 000 = 1100 / t
t = 1100 / 15 000
(t =) 0.073 (s)
(c) idea that airbag increases the (collision) time;
reduces the rate of change of momentum;
Questions 5
(a) Topic – 4.c
(b) Topic-4.c
This question is about specific heat capacity.
(a) State what is meant by the term specific heat capacity.
(b) The diagram shows a sample of solid stearic acid being heated in a boiling tube using a water bath.
The mass of stearic acid in the boiling tube is 58g. When the boiling tube is placed in the water bath, the temperature of the stearic acid increases from 21°C to 37°C. The stearic acid does not melt. As the temperature of the stearic acid increases, an additional 3500J of energy needs to be transferred electrically to the water bath.
(i) Using this data, show that the specific heat capacity of the solid stearic acid is approximately 4J/g°C.
(ii) The true value for the specific heat capacity of solid stearic acid is 2.3J/g°C. Give a reason for the difference between the value in (i) and the true value.
▶️Answer/Explanation
Ans
(a) energy required;
for a unit mass / per gram (of mass) / per kilogram (of mass);
to change per unit temperature / change by 1°(C) / change by 1 K;
(b) (i) substitution into ∆Q = mc∆T;
rearrangement;
correct evaluation to 2 or more s.f.;
e.g.
3500 = 58 × c × [37−21]
c = 3500 / 58 × 16
c = 3.8
(ii) any one from:
MP1. energy also heating boiling tube;
MP2. energy is being transferred/lost to/gained from surroundings;
MP3. stearic acid may be impure;
Questions 6
(a) Topic – 7.c
(b) Topic- 7.c
This question is about electromagnetism.
(a) Diagram 1 shows the magnetic field around a straight section of copper wire.
Explain why the copper wire has the magnetic field shown in the diagram.
(b) A student investigates how the strength of an electromagnet varies with the current in the electromagnet. The diagram shows their apparatus
This is the student’s method.
• switch on the electromagnet at its maximum current
• place a load of 100g so that it is held above the floor by the electromagnet
• slowly reduce the current in the electromagnet until the load falls from the electromagnet
• record the current at which the load falls
• record the current at which the same load falls two more times
Repeat the method for loads of different masses.
(i) Suggest a suitable safety precaution for the student’s investigation.
(ii) The table shows the student’s results.
Calculate the mean current when the mass of the load was 600 g. Give your answer to a suitable number of significant figures.
(iii) On the grid, plot a graph of the mean current against the mass of the load. The scale for the mass axis has been done for you.
(iv) Draw the line of best fit.
(v) The student predicts that a load of 1.0kg will fall when the current in the electromagnet is 3.0A. Comment on the student’s prediction.
▶️Answer/Explanation
Ans
(a) idea that there must be a current in the wire;
this current must be to the right;
(b) (i) any one of:
MP1. idea of avoiding fall objects from hitting hands/feet etc;
MP2. taking care of heating effect of current;
MP3. idea of protecting floor from damage;
(ii) correct calculation of mean;
answer given to 3 significant figures;
e.g.
(mean current =) 1.833…(A)
(mean current =) 1.83 (A)
(iii) y-axis scale with a sensible, continuous scale such that plotted data covers 50% of the grid;
y-axis labelled with current/I AND amps/A;
all data plotted correctly;
(iv) straight line drawn with approximately equal distribution of points either side;
(v) any three from:
MP1. indication that 1.0 kg is 1000 g;
MP2. use of data from table to show that ratio supports 3.0 A current value;
MP3. (because) current is (directly) proportional to mass;
MP4. idea that 1.0 kg is (far) beyond range of collected data/graph;
MP5. idea that pattern may not continue outside range of data collected/graph;
Questions 7
(a) Topic – 5.b
(b) Topic- 5.b
(c) Topic- 5.b
This question is about sound waves.
(a) The table gives the frequencies of some different sound waves. Place ticks in the table to show which sound waves can be heard by humans.
(b) The diagram shows the screen of an oscilloscope when a sound wave is detected. Add to the diagram by drawing the trace of another sound wave that has a lower pitch and is quieter than the sound wave shown. 
(c) The speed of sound in air varies with temperature. A student finds a formula in a textbook that links the speed of sound waves in air to the temperature of the air, measured in kelvin.
speed of sound in air = (0.606×temperature in kelvin) + 166
(i) Calculate the speed of sound when the air temperature is 46°C.
(ii) Calculate the wavelength of a sound wave with a frequency of 15000Hz when the air temperature is 46°C.
▶️Answer/Explanation
Ans
(a) C and D ticked with A and F unticked = 1 mark;
all of B, C, D and E ticked with A and F unticked = 2 marks;;
(b) wave drawn with lower amplitude throughout;
wave drawn with lower frequency throughout;
(c) (i) conversion of temperature into kelvin;
substitution and evaluation;
e.g.
temperature = 46 + 273 = 319 K
speed = (0.606 × 319) + 166 = 360 (m/s)
(ii) substitution into speed = frequency × wavelength;
rearrangement;
evaluation;
e.g.
360 = 15 000 × wavelength
wavelength = 360 / 15 000
(wavelength =) 0.024 (m)
Questions 8
(a) Topic – 9.b
(b) Topic-9.b
(c) Topic-9.d
This question is about stars.
(a) The table gives some information about four stars.
(i) Star C is much more powerful than star A. Stars A and C appear to have the same brightness when viewed from Earth. Suggest how this is possible.
(ii) Using information from the table, explain which star is in the supernova stage of its evolution.
(b) Explain how a main sequence star evolves into a supernova.
(c) Astronomers have used supernovas in distant galaxies to investigate the expansion of the universe.
(i) Light emitted from a supernova at a wavelength of \(7.774 \times 10^{–7} m\) was detected at Earth with a wavelength of \(7.780 \times 10^{–7} m\). Calculate the speed at which the galaxy containing this supernova was moving away from the Earth. [speed of light = \(3.0 \times 10^8 m/s\)]
(ii) The astronomers investigated supernovas that showed a red-shift in the wavelengths detected in different galaxies. The astronomers discovered that the red-shifted light detected from supernovas in nearby galaxies had shorter wavelengths than the red-shifted light detected from supernovas in galaxies further away. Explain how this discovery supports the Big Bang theory.
▶️Answer/Explanation
Ans
(a) (i) idea that star A is closer (to Earth than star C);
(ii) star D;
(because) it (is the only star that) has a mass (much) larger than the mass of the Sun;
(because) it has a much lower value of absolute magnitude;
(b) any three from:
MP1. (hydrogen) fusion stops (in core);
MP2. core collapses; allow core contracts
MP3. (which) restarts fusion (in core);
MP4. star becomes red supergiant; allow super red giant
MP5. fusion of heavier elements stops (in core);
MP6. star explodes (as supernova);
(c) (i) evaluation of change of wavelength;
substitution into ∆λ/λ = v/c;
rearrangement;
evaluation of speed;
e.g.
\(∆λ = (7.780-7.774) = 6 × 10^{−10} (m)\)
\(6 × 10^{−10} / 7.774 × 10^{−7} = v / 3.0 × 10^8\)
\(v = 6 × 10^{−10} / 7.774 × 10^{−7} × 3.0 × 10^8\)
\((v =) 2.315 × 10^5 (m/s)\)
(ii) MP1. nearby galaxies show smaller {red-shift / change in wavelength};
MP2. nearby galaxies are travelling slower than further galaxies;
MP3. (all light red-shifted) suggests universe is expanding;
MP4. suggesting universe was once at a single point;