4PH1/2P — June 2023 (Edexcel IGCSE Physics): Past Paper

A pencil has a weight of 0.16 N.

What is the mass of the pencil?

The diagram shows the pencil with one end resting on a small block. F 7.4 cm pivot 3.7 cm 0.16 N A finger provides an upwards force, F, to keep the pencil horizontal.

The weight of the pencil is 0.16 N. Calculate the moment of the weight of the pencil about the pivot. Use the formula moment = force × perpendicular distance from the pivot moment = N cm

State the moment of the force F. moment = N cm

Show that force F is 0.080 N.

A solid bar of chocolate is taken from a refrigerator. (Source: © MarySan/Shutterstock)

The temperature of the chocolate bar is 5 °C. Describe the arrangement and motion of the particles inside the chocolate bar.

The chocolate is heated at a constant rate until the temperature reaches 45 °C. The chocolate has a melting point of 32 °C and a boiling point of 55 °C.

Describe the motion of the particles in the chocolate when the chocolate is at a temperature of 45 °C.

Which of these is used to measure the temperature of the chocolate?

Use the axes to sketch a graph of how the temperature of the chocolate changes with time when it is heated from 5 °C to 45 °C. Temperature in °C Time

The diagram shows the inside of an oscilloscope. Electrons leave the electron supply and accelerate towards the screen. The stream of electrons hits the screen. – + stream of electrons electron supply positively charged screen grid

The grid is connected to the positive terminal of a high voltage power supply.

Explain, in terms of the movement of particles, how the grid has become positively charged.

No printed figure accompanies this part — in the paper you would draw the diagram (or label the apparatus) in the answer space provided.

State the formula linking kinetic energy, mass and speed.

Calculate the speed of an electron when it has 1.3 × 10 –15 J of kinetic energy. The mass of an electron is 9.1 × 10 –31 kg. speed = m / s

The stream of electrons spreads out as it travels towards the screen. Explain why the electrons in the stream move apart from each other.

The oscilloscope can cause the electrons to move in a circle. This produces a circular pattern on the screen. 1 cm 1 cm

Use the scale to determine the radius of the circle. radius = cm

The time taken for the electrons to complete one orbit of the circle is 24 ms. Calculate the orbital speed of the electrons. Use the formula 2π × orbital radius orbital speed = time period orbital speed = m / s

The diagram shows two birds, just before bird X catches the smaller bird Y. Both birds are travelling horizontally at constant velocity. bird X bird Y velocity = 13 m / s velocity mass = 0.41 kg

Show that the momentum of bird X is about 5 kg m / s.

The momentum of bird Y just before it is caught is 0.15 kg m / s. Calculate the total momentum of the birds just before bird X catches bird Y. momentum = kg m / s

State the total momentum of the birds just after bird X has caught bird Y. momentum = kg m / s

Bird Y has a mass of 0.17 kg. Calculate the velocity of the birds just after bird X has caught bird Y. velocity = m / s

The diagram shows some of the components of a nuclear fission reactor. control rod coolant out moderator reactor vessel fuel rod coolant in

Describe how a chain reaction occurs in a nuclear fission reactor.

Describe the role of the control rods in a nuclear fission reactor.

Describe how the process of nuclear fission is different from the process of nuclear fusion.

Which of these is the name of the nuclear process that is the main energy source for stars?

Give a reason why the nuclear process in stars does not happen at low temperatures and pressures.

The National Grid is used in the United Kingdom for the large-scale transmission of electricity. The photograph shows solar panels connected to the National Grid. (Source: © Jenson/Shutterstock)

Solar panels provide direct current to a device that outputs an alternating current so that the energy from the solar panels can be supplied to the National Grid.

Explain why a step-up transformer is used to supply the National Grid.

No printed figure accompanies this part — in the paper you would draw the diagram (or label the apparatus) in the answer space provided.

This is the label on the step-up transformer. input voltage = 15 kV output voltage = 340 kV number of turns on primary coil = 1400 State the formula linking input voltage, output voltage and turns ratio for a transformer.

Calculate the number of turns on the secondary coil of the step‑up transformer. number of turns =

Solar panels produce constant direct current (d.c.). Explain why a transformer will not work when connected to constant direct current.

A glass prism can be used to refract light. prism i r

State the name of the piece of equipment used to measure angles.

Measure the angle of incidence and the angle of refraction for the light entering the prism. angle of incidence = degrees angle of refraction = degrees

State the formula linking refractive index, angle of incidence and angle of refraction.

Calculate the refractive index of the glass. refractive index =

Two galaxies, A and B, emit red light with a reference wavelength of 630 nm. An astronomer measures the wavelength of red light from galaxy A when the light arrives at the Earth. The astronomer’s value for the wavelength is 645 nm.

Calculate the difference between the astronomer’s value for the wavelength and the reference wavelength of red light. difference in wavelength = nm

The change in wavelength happens because galaxy A is moving away from the Earth. Calculate the speed of galaxy A. [speed of light = 3.0 × 10⁸ m / s] speed = m / s

Light from galaxy B has twice the redshift as light from galaxy A. Galaxy B is twice as far away from Earth as galaxy A. Explain how these observations support the Big Bang theory of the origin of the Universe.

Concrete on top of buildings can be used to heat water. The photograph shows a concrete and water heating system being built into the roof of a house. (Source: © ejhgndrn/Shutterstock)

A scientist wants to determine the specific heat capacity of concrete. The diagram shows some of the equipment they could use. 12 V A V lid insulating material concrete thermometer electrical heater Describe a suitable method to find the specific heat capacity of concrete.

Explain the advantage of the concrete having a high specific heat capacity when it is used to heat water in the heating system.