P4.3.1 · Nuclear equations and half-lives
Explain — 4 marks
A student investigates the properties of different materials by heating them in a Bunsen burner flame. She observes that copper conducts heat quickly along its length, while a wooden rod does not conduct heat effectively in the same way. The student wants to understand why these materials behave differently.
-
(a) Explain why copper is a good thermal conductor.
[2 marks]
-
(b) Explain why wood is a poor thermal conductor.
[1 mark]
-
(c) The student uses the wooden rod as a handle to hold the copper rod in the flame. Explain why this is a safe procedure.
[1 mark]
Show mark scheme
- (a) Copper contains free electrons (or delocalised electrons) that can move through the material
- (a) These electrons transfer thermal energy (or heat) quickly from the hot end to the cooler end
- (b) Wood has no free electrons (or electrons are not delocalised/are fixed in atoms) so heat cannot be conducted efficiently by electron movement
- (c) Wood is a poor thermal conductor, so heat does not conduct along the wooden rod to the student's hand, keeping it safe from burns
P7.2 · The motor effect
State — 3 marks
A student is investigating how an electric cooling fan works. The fan contains a simple DC motor. When the motor is switched on, a current flows through a coil of wire that is placed between the poles of a permanent magnet. This causes the coil to spin.
-
(a) State what must happen for a force to act on the wire in the coil.
[1 mark]
-
(b) State two factors that affect the size of the force on the wire.
[2 marks]
Show mark scheme
- (a) current flows through wire/conductor (in magnetic field)
- (b) strength of magnetic field / magnetic flux density
- (b) size of current
- (b) length of wire/conductor in the field
P2.5 · Static electricity
State — 4 marks
A student rubs a polythene rod with a duster. The rod becomes negatively charged and is then brought near to small pieces of paper on a desk. The paper pieces are attracted to the rod even though they are initially uncharged.
-
(a) State what happens to electrons in the polythene rod during the rubbing process.
[1 mark]
-
(b) State the type of charge induced on the surface of the paper pieces that face the negatively charged rod.
[1 mark]
-
(c) State two reasons why the paper pieces are attracted to the rod despite being initially uncharged.
[2 marks]
Show mark scheme
- (a) Electrons are transferred from the duster to the polythene rod / electrons move onto the polythene rod (1 mark)
- (b) Positive charge is induced on the surface of the paper facing the rod (1 mark)
- (c) The negatively charged rod repels electrons in the paper, leaving a positive charge on the near surface (1 mark)
- (c) Opposite charges attract, so the positive charge on the paper is attracted to the negative charge on the rod (1 mark)
P5.8 · Newton's Laws
Suggest — 5 marks
A stunt driver is planning a scene where a car must accelerate rapidly from rest and then brake suddenly to avoid an obstacle. The car has a mass of 1200 kg. During acceleration, the engine provides a driving force, and during braking, friction acts on the wheels. The driver is concerned about passenger safety and the structural integrity of the vehicle during both phases of motion.
-
(a) During the acceleration phase, the driving force from the engine is 4800 N and the resistance forces total 1200 N. Calculate the acceleration of the car.
[2 marks]
-
(b) Suggest why the passengers experience a backward force during the acceleration phase, referring to Newton's laws in your answer.
[2 marks]
-
(c) The car reaches a velocity of 20 m/s before braking. The braking force is 6000 N. Suggest what additional safety consideration the stunt coordinator should make regarding the magnitude of the braking force and explain your reasoning using Newton's second law.
[1 mark]
Show mark scheme
- (a) Net force = 4800 - 1200 = 3600 N (1 mark)
- (a) Acceleration = F/m = 3600/1200 = 3 m/s² (1 mark)
- (b) Passengers have inertia and tend to remain at rest (Newton's first law) (1 mark)
- (b) The car accelerates forward beneath them, so they appear to move backward relative to the car / the seat must exert a forward force to accelerate the passengers (1 mark)
- (c) Excessive braking force could cause deceleration that is too large / a = F/m = 6000/1200 = 5 m/s², which could cause injury to passengers or damage to the vehicle structure / the passengers would experience a large inertial force forward (1 mark)
P4.1.3 · Developing the model of the atom
Suggest — 2 marks
A student is investigating how the extension of a spring changes when different masses are hung from it. The student suspends the spring vertically from a clamp stand and measures the extension using a ruler. The spring obeys Hooke's law up to a certain load.
-
(a) The student hangs a 500 g mass from the spring and measures an extension of 8 cm. When a 1000 g mass is hung from the spring, the extension is 16 cm. Suggest why the extension doubles when the mass doubles.
[1 mark]
-
(b) The student continues to add more mass and finds that when a 5000 g mass is hung from the spring, the extension is only 35 cm rather than the expected 40 cm. Suggest what this indicates about the spring.
[1 mark]
Show mark scheme
- (a) Accept: the spring obeys Hooke's law (or the extension is proportional to the load/force) / the force/weight doubles so the extension doubles / F = kx relationship / force is directly proportional to extension. Do not accept vague answers such as 'because it's heavier'.
- (b) Accept: the spring has exceeded its elastic limit / the spring is no longer obeying Hooke's law / the spring has become permanently deformed / plastic deformation has occurred. Accept: the spring constant has changed or decreased. Do not accept 'the spring is broken'.
P2.3.2 · Domestic uses and safety
Describe — 5 marks
A coastal town is considering options for a new power station. The local council must choose between a nuclear power station, an offshore wind farm, or a natural gas power station. Each option has different implications for the environment, energy security, and running costs.
-
(a) Describe two advantages of using a nuclear power station to generate electricity compared to a natural gas power station.
[2 marks]
-
(b) Describe how the use of renewable energy resources for electricity generation in the UK has changed over the past 20 years and explain one factor that has caused this change.
[3 marks]
Show mark scheme
- (a) no greenhouse gases / carbon dioxide produced (during operation)
- (a) very high energy density / small amount of fuel produces large amount of energy
- (a) reliable / not dependent on weather / can operate continuously
- (a) fuel is relatively cheap (per unit of energy output)
- (b) use of renewable resources has increased
- (b) government targets / international agreements have encouraged investment
- (b) concern about climate change / reducing carbon emissions
- (b) improved technology has made renewables more efficient / cheaper
- (b) depletion of fossil fuels / need for energy security
P2.1.4 · Current, potential difference and resistance
Calculate — 2 marks
A student is investigating how the resistance of a thermistor changes with temperature. The thermistor is used in a temperature sensor circuit. At 20°C, the thermistor has a resistance of 2000 Ω. The student connects the thermistor to a 6.0 V battery and measures the current.
-
(a) Calculate the current through the thermistor at 20°C.
Use the equation: $I = \frac{V}{R}$
[1 mark]
-
(b) When the temperature increases to 40°C, the resistance of the thermistor decreases to 800 Ω. Calculate the new current through the thermistor.
[1 mark]
Show mark scheme
- (a) $I = \frac{6.0}{2000}$ or 0.003 (A)
- (a) 0.003 A / 3 mA (allow 0.003 with any valid unit)
- (b) $I = \frac{6.0}{800}$ or 0.0075 (A)
- (b) 0.0075 A / 7.5 mA (allow 0.0075 with any valid unit)
P2.2.2 · Series and parallel circuits
Calculate — 5 marks
A student is designing a lighting system for a stage display. The display uses three identical spotlights connected in parallel to a 12 V power supply. Each spotlight has a resistance of 24 Ω. The student needs to calculate the total current drawn from the power supply to ensure the correct fuse is used.
-
(a) Calculate the total resistance of the three spotlights connected in parallel.
[2 marks]
-
(b) Calculate the total current drawn from the 12 V power supply. Give your answer to 2 significant figures.
[3 marks]
Show mark scheme
- (a) 1/24 + 1/24 + 1/24 = 3/24 = 1/8 (ecf)
- (a) 1 ÷ (1/8) = 8 Ω
- (b) I = V ÷ R
- (b) 12 ÷ 8
- (b) = 1.5 A (ecf from 01.1)
P6.2 · Electromagnetic waves
Suggest — 5 marks
A hospital uses different types of electromagnetic radiation for medical imaging and treatment. X-rays are used to detect broken bones, while infrared cameras monitor patient temperature during surgery. The hospital's wireless communication system transmits data using radio waves. All these electromagnetic waves travel at the same speed through a vacuum, but they have different wavelengths and frequencies.
-
(a) The hospital needs to choose between using X-rays or infrared radiation to detect a hairline fracture in a patient's ankle. Suggest which type of electromagnetic radiation would be more suitable and explain your choice in terms of the properties of electromagnetic waves.
[2 marks]
-
(b) A trainee technician claims that infrared waves travel faster than radio waves because infrared has a higher frequency. Suggest why this statement is incorrect and use your knowledge of the electromagnetic spectrum to support your answer.
[2 marks]
-
(c) The hospital is upgrading its wireless communication system. Suggest one reason why radio waves are chosen for transmitting data over long distances in the hospital rather than visible light, considering the properties and applications of electromagnetic waves.
[1 mark]
Show mark scheme
- (a) X-rays are more suitable because they have shorter wavelengths/higher frequency than infrared
- (a) X-rays can penetrate soft tissue and are absorbed by denser material (bone), allowing fractures to be detected
- (b) All electromagnetic waves travel at the same speed in a vacuum (or same speed through air)
- (b) Frequency and wavelength are inversely related but speed remains constant; higher frequency does not mean faster speed
- (c) Radio waves have longer wavelengths so they diffract around obstacles/walls in the hospital, whereas visible light travels in straight lines and is easily blocked
P8.3.2 · Red-shift
Describe — 3 marks
A student investigating electromagnetic induction sets up an experiment where a magnet is repeatedly pushed into and pulled out of a coil of wire connected to a galvanometer. The galvanometer needle deflects each time the magnet moves, but the direction and magnitude of the deflection change depending on the direction of motion.
-
(a) Describe what happens to the galvanometer reading as the magnet is pushed into the coil.
[1 mark]
-
(b) Describe how the galvanometer reading when the magnet is pulled out of the coil differs from when it is pushed in.
[1 mark]
-
(c) Describe the relationship between the speed at which the magnet moves and the magnitude of the galvanometer deflection.
[1 mark]
Show mark scheme
- (a) The galvanometer needle deflects in one direction / shows a reading when the magnet enters the coil
- (b) The galvanometer needle deflects in the opposite direction when the magnet is pulled out / the reading reverses
- (c) The faster the magnet moves, the greater the magnitude of the galvanometer deflection / the induced EMF/current is greater at higher speeds
P5.5 · Pressure in a fluid
Compare — 2 marks
A scuba diver descends into the ocean. At a depth of 10 metres, the pressure is approximately 200 kPa. At a depth of 20 metres, the pressure is approximately 300 kPa.
-
Compare the pressure acting on the diver at 10 metres depth with the pressure acting on the diver at 20 metres depth.
[2 marks]
Show mark scheme
- The pressure at 20 metres is greater than the pressure at 10 metres (or pressure increases with depth)
- The pressure at 20 metres is 100 kPa more than at 10 metres (or difference of 100 kPa / pressure increases by 50% / ratio comparison such as 300:200 or 3:2)
P3.2.3 · Internal energy and energy transfers
Compare — 2 marks
A student investigates the motion of two different objects rolling down an inclined plane. Object A is a solid sphere and Object B is a hollow sphere, both with the same mass and radius. The plane is inclined at 30° to the horizontal.
-
Compare the acceleration of the solid sphere (Object A) with the hollow sphere (Object B) as they roll down the inclined plane without slipping.
[2 marks]
Show mark scheme
- States that the solid sphere accelerates faster than the hollow sphere OR identifies that the solid sphere has a smaller moment of inertia
- Explains that for rolling motion without slipping, the moment of inertia affects how energy is distributed between translational and rotational kinetic energy, meaning the solid sphere converts more gravitational potential energy into translational motion
GCSE Perfect