4PH1/2P — January 2022 (Edexcel IGCSE Physics): Past Paper

Which of these is a device used to measure force?

Airbags are safety devices used in cars to protect the driver if there is a crash.

State the formula linking momentum, mass and velocity.

A person inside a car has a mass of 72 kg and a velocity of 13 m/s. Show that the momentum of the person is about 900 kg m/s.

The person experiences a crash and comes to rest in 0.29 s. Calculate the force on the person. force = N

Which statement explains how airbags protect the driver?

Describe the arrangement and motion of particles in a solid. You may draw a diagram to help your answer.

A solid changes state by melting at a certain temperature. For phosphorus, this change of state occurs at 44 °C. Sketch how the temperature of a sample of phosphorus changes when it is heated at a constant rate from –40 °C to 80 °C. Temperature in °C 0 Time –20 –40

Nuclear fusion is a process that occurs in the core of stars.

Which is the best description of nuclear fusion?

Two nuclei are close together and stationary. Explain why these nuclei will move apart.

Describe the conditions needed for fusion to occur in the core of a star.

A student investigates how the strength of the magnetic field from a solenoid changes with distance from the end of the solenoid. The diagram shows the solenoid connected to a power supply. distance

The student uses a device called a Hall probe, which can be placed anywhere in the magnetic field to measure its strength at that point. Design a suitable method for the investigation. Your answer should include • any extra measuring equipment needed • details of the independent variable, dependent variable and any control variables You may include a diagram to help your answer.

The graph shows the results of the student’s investigation. Strength of magnetic field in arbitrary units 0 10 20 30 40 50 Distance in cm The student suggests that the relationship linking the strength of the magnetic field and the distance from the end of the solenoid is strength of magnetic field × (distance)³ = constant Use readings from the graph to deduce whether the results of the student’s investigation support this relationship.

The diagram shows a ball at the bottom of a ramp. The ball moves up the ramp with an initial speed v. v 29 cm ball

State the formula linking gravitational potential energy (GPE), mass, gravitational field strength (g) and height.

The ball has a mass of 14 g. Show that when the ball reaches a height of 29 cm above the bottom of the ramp, the GPE gained by the ball is about 4 × 10⁻² J.

At the bottom of the ramp, the 14 g ball has a kinetic energy (KE) of 5.1 × 10⁻² J. Calculate the speed of the ball at the bottom of the ramp. speed = m/s

The ball is stationary when it reaches the top of the ramp. There is a difference between the KE of the ball at the bottom of the ramp and the GPE of the ball at a height of 29 cm above the bottom of the ramp. Explain why the work done by friction between the ball and the ramp is equal to this difference.

Magnetic Resonance Imaging (MRI) machines can take scans of the inside of a patient.

There is an electromagnet inside the MRI machine. Describe the construction of an electromagnet. You may draw a diagram to help your answer.

During the scan, music can be played through a loudspeaker to the patient. The oscilloscope trace in the diagram represents a sound played to the patient. Oscilloscope settings: 0 y direction: 1 square = 0.5 V x direction: 1 square = 0.5 ms

Determine the period of the sound wave. period = s

Calculate the frequency of the sound wave. frequency = Hz

Deduce whether humans can hear the sound wave.

The current in the loudspeaker is alternating current (a.c.). Give the evidence from the oscilloscope trace to support this statement.

Draw the circuit symbol for an a.c. power supply.

The photographs show two large-scale electrical production methods

• a hydroelectric power (HEP) station
• a wind farm (Source: © Bryan Busovicki/Shutterstock) (Source: © Tom Buysse/Shutterstock) Hydroelectric power station Wind farm

Discuss the advantages and disadvantages of using hydroelectric power stations compared with wind farms for large-scale electricity production.

Describe the energy transfers that are involved in generating electricity in a hydroelectric power station.

A galaxy moves away from the Earth at a speed of 3.9 × 10⁴ km/s. The speed of light is 3.0 × 10⁵ km/s. Light from the galaxy is emitted with a wavelength of 6.2 × 10⁻⁷ m. Calculate the change in the wavelength of the light that is received by an observer on the Earth. change in wavelength = m

Calculate the wavelength of light that is received by an observer on the Earth. wavelength = m

One of the pieces of evidence for the Big Bang theory is the red-shift of galaxies. Explain how the red-shift of galaxies supports the Big Bang theory.

A student uses a small iron nail and a beaker of water to estimate the temperature of a flame. The diagram shows some of the equipment used. nail flame beaker heatproof mat water This is the student’s method

• place a thermometer into the beaker of water
• record the temperature of the water
• heat the nail in the flame for a long period of time
• quickly move the nail into the beaker of water
• record the highest temperature of the water

State a safety precaution the student should take.

While in the water, the thermal energy store of the nail decreases and the thermal energy store of the water increases until their temperatures are the same. The energy lost from the nail is equal to the energy gained by the water. The table shows the student’s results. Mass of water in g 138 Specific heat capacity of water in J/kg °C 4200 Temperature change of water in °C 5.0 Mass of nail in g 4.8 Specific heat capacity of iron in J/kg °C 450

Show that the energy gained by the water is approximately 3000 J.

Calculate the temperature change of the nail. Temperature change = °C

Give a reason why the calculated temperature change of the nail is lower than the actual temperature change.