4PH1/2P — June 2021 (Edexcel IGCSE Physics): Past Paper

This is an incomplete Hertzsprung-Russell diagram. Absolute magnitude Temperature

Which of these is in the shaded area of the diagram?

On the diagram, draw the area to show the position of white dwarf stars. Label this area WD.

On the diagram, draw the area to show the position of red giant stars. Label this area RG.

State what is meant by the term absolute magnitude.

The Sun emits various parts of the electromagnetic spectrum.

Which part of the electromagnetic spectrum causes damage to human surface skin cells?

Which of these increases the risk of damage to human surface skin cells?

Two students investigate the speed of sound. Student A has a device that makes a loud sound. Student B has a stopwatch. A sound wave travels from student A to the wall and is reflected back to student B. not to scale wall 210 metres 120 metres A B

Calculate the total distance the sound wave travels from student A to the wall and back to student B. distance = m

Student B hears the sound before and after the sound wave reflects from the wall. When student B hears the sound before reflection, he starts the stopwatch. When student B hears the sound after reflection, he stops the stopwatch. The students repeat this experiment five times. The table shows the students’ results. Time in s 0.50 0.62 0.52 0.58 0.55 Calculate the mean (average) time. Give your answer to 2 significant figures. mean time = s

Calculate the speed of sound for this investigation. speed = m/s

Suggest a reason why the students’ results are not always the same.

The diagram shows part of a radio antenna. The plastic tube protects the radio antenna from bad weather. Dust particles carried by the wind rub against the plastic tube. After some time, the dust particles cause the tube to become positively charged. plastic tube antenna metal mast wire attached to Earth

State the property of plastic that allows it to become electrostatically charged.

Explain how the plastic tube becomes positively charged.

The plastic tube is attached to a metal mast. This would cause the metal mast to become positively charged. Explain why there is a wire connecting the metal mast to the Earth.

The plastic tube gains a charge of 4.3 mC. The energy stored on the tube is 3.7 J. Calculate the voltage between the plastic tube and the metal mast. voltage = V

An engineer is working on the radio antenna. Describe the hazard to the engineer if there is no earth wire.

A student investigates a sound wave with a frequency of 25 000 Hz.

Calculate the wavelength of this sound wave. [speed of sound = 330 m/s] wavelength = m

The oscilloscope trace represents the sound wave. Oscilloscope settings y direction: 1 square = 5 V x direction: 1 square = 0.01 ms Determine the amplitude of the oscilloscope trace. amplitude = V

Diagram 1 shows a coil of wire wrapped around a cardboard tube. The coil is fixed to the cardboard tube. On diagram 1, draw field lines to represent the magnetic field produced when the current is in the direction shown. Diagram 1

Diagram 2 shows a model of a loudspeaker that uses the coil and the cardboard tube. The cardboard tube is fixed to a thin piece of card, which is clamped at both ends. cardboard tube card coil to alternating current supply bar magnet Diagram 2 The student holds a bar magnet near the bottom of the cardboard tube. Explain why this causes the loudspeaker to produce a sound.

When the frequency of the alternating current is 10 kHz, the student hears a sound. The student increases the frequency of the alternating current to 25 kHz. Explain why the student cannot hear a sound now, even though the card is still vibrating.

Suggest a change to the apparatus that would increase the loudness of the sound when the frequency of the alternating current is 10 kHz.

The diagram shows some of the apparatus a student uses to investigate the effect of heating a solid substance. 12 V supply lid insulating material beaker thermometer solid substance electrical heater

Describe how the student could use their apparatus to help determine the specific heat capacity of the substance. You should give details of any additional apparatus needed in your answer.

The student continues to heat the substance, keeping the power of the heater constant. The graph shows how the temperature of the substance changes with time. Temperature in °C Time

Use the graph to determine the melting point of this substance. melting point = °C

Describe, in terms of particles, what is happening in the substance when the graph line is horizontal.

Suggest why the two non-horizontal lines on the graph have different gradients.

This is a question about a nuclear fusion power station.

Explain what happens during nuclear fusion.

The diagram shows how a fusion power station could supply the National Grid in the future. pylon, 330 kV fusion power station 28 kA, 21 kV step-up transformer

State the main method of energy transfer from the fusion power station generator to the primary coil of the step-up transformer.

The fusion power station could supply the input coil of the step-up transformer with a current of 28 kA at a voltage of 21 kV. The output coil of the transformer has a voltage of 330 kV. Assume the transformer is 100% efficient. Calculate the current in the output coil of the transformer. current = kA

The diagram shows two blocks at rest on a table, viewed from above. A spring is attached to the large block. The small block is attached by a piece of string to a fixed point on the table. A student pushes the two blocks together so that the spring is compressed. fixed point large block small block mass 75 g mass 17 g spring

The student releases the blocks. The kinetic energy (KE) store of the small block is 0.29 J when the blocks are no longer in contact. Show that the speed of the small block is about 6 m/s.

Using ideas about momentum, show that the speed of the large block is about 1 m/s after the blocks are no longer in contact.

The small block takes 0.11 s to reach 6 m/s. Calculate the mean force exerted on the small block by the spring. mean force = N

The small block then moves around the fixed point on the table. The block moves in a circular orbit of radius 17.6 cm at a constant orbital speed of 6 m/s. The time period of the orbit can be found using the formula 2π × orbital radius orbital speed = time period Calculate the time period of the orbit. time period = s