OCR GCSE Physics A (Gateway) Paper 4 Higher November 2021 question paper J249/04

A student makes a wave in a ripple tank.

The student measures distance, L.

What is the wavelength of the wave?

A 2.4 cm

B 4.0 cm

C 4.8 cm

D 24 cm

Which statement about infra red radiation is correct?

A Infra red has the shortest wavelength in the electromagnetic spectrum.

B Infra red is emitted by humans.

C Infra red is next to radio waves in the electromagnetic spectrum.

D White objects absorb more infra red than black objects.

Estimate the force needed to accelerate a car at 1 m / s². 4

A 10 N

B 100 N

C 1000 N

D 10 000 N

How can unwanted energy transfer be reduced?

A By adding lubrication

B By decreasing efficiency

C By increasing friction

D By removing thermal insulation

A cork floats on water. Ripples move across the surface of the water.

Which statement describes the motion of the cork?

A It does not move.

B It moves in the same direction as the direction of movement of the ripples.

C It moves sideways parallel to the direction of movement of the ripples.

D It moves up and down.

The two statements describe the mains electricity supply:

• The a.c. potential difference between the earth wire and the live wire is X volts.

• The a.c. potential difference between the earth wire and the neutral wire is Y volts.

Which row of the table correctly completes the sentences?

Four stages in the lifecycle of a star are P, Q, R and S:

What is the correct order of these stages?

Which answer equals 2.45 × 10⁹ Hz? 9

A 2.45 GHz

B 2.45 kHz

C 2.45 MHz

D 2.45 THz

A student uses a glass prism to split white light into different colours.

Which statement describes the light in the prism?

A Blue light is refracted less than red light.

B Blue light slows down more than red light.

C Red light has a shorter wavelength than blue light.

D Red light has a smaller frequency change than blue light.

A teacher measures the activity of a radioactive source. They place different materials between the radioactive source and detector.

The results are shown in the table:

Which type of radiation is emitted by the radioactive source?

A Alpha and beta particles only

B Alpha particles only

C Beta particles only

D Gamma rays and beta particles only

An electrical circuit has an alternating current.

What type of wave can be produced by the alternating current?

A Gamma rays

B Radio

C Ultraviolet

D X-rays

An atom loses an electron after absorbing some electromagnetic radiation.

Which row of the table describes what happens?

Two students, A and B, climb some steps.

• Student A has twice the mass of student B.

• Student B climbs four times higher than student A.

Which statement about gravitational potential energy (GPE) is correct?

Use the equation: potential energy = mass × height × gravitational field strength

A GPE gain of student B = ¼ × GPE gain of student A

B GPE gain of student B = ½ × GPE gain of student A

C GPE gain of student B = 2 × GPE gain of student A

D GPE gain of student B = 4 × GPE gain of student A

This question is about visible light.

State one change that happens to light when it travels from water into air.

Diagram in Fig. 16.1 shows a ray of light from a fish in a container of water.

Complete the ray diagram in Fig. 16.1 to show the path of the ray after it leaves the water.

Include a normal line in your diagram.

Diagram in Fig. 16.2 shows three incident rays hitting the surface of the fish. Light is scattered from the surface of the fish.

Complete the diagram in Fig. 16.2 to show the scattered rays.

The fish appears red under white light.

Explain why the fish appears black under green light.

A solar cell changes light into electricity. Solar panels contain solar cells.

A student investigates a solar cell:

• They change the intensity of the light.

• They measure the potential difference across the solar cell.

The light intensity is changed to 2.00 W / m².

Use your graph to predict the potential difference of the solar cell.

Show your working on the graph.

Suggest one way the student could improve their investigation.

More people use solar panels to generate electricity compared to twenty years ago.

Suggest two reasons why.

A homeowner fits solar panels to the roof of their house.

Table 17.2 gives the energy values for the house for one day:

Explain whether the energy needed by all the appliances can be generated using only solar panels.

Use Table 17.2 and your knowledge of solar panels to explain your answer.

This question is about radioactive Plutonium-238 (Pu-238).

Pu-238 can be used to produce electricity:

• The Pu-238 undergoes radioactive decay.

• This causes the temperature of the plutonium to increase.

• Electricity is produced.

Complete the sentences using the words below.

You can use each word once, more than once, or not at all.

chemical
elastic potential
electrostatic

gravitational potential
nuclear
thermal

The........ energy store of the plutonium decreases.

The........ energy store of the plutonium increases.

State why Pu-238 undergoes radioactive decay.

Fig. 18.1 shows how the activity of Pu-238 changes with time.

Use Fig. 18.1 to find the half-life for Pu-238.

Show your working on the graph.

A different isotope of plutonium is used in nuclear fission.

Describe how a chain reaction occurs in nuclear fission.

Nuclear fusion occurs in the Sun.

Describe what is meant by nuclear fusion.

A radio signal is sent to Mars.

Table 19.1 shows the distance from the Sun to Earth and the distance from the Sun to Mars, when Mars and Earth are closest.

The radio signal travels at 300 000 000 m / s.

Calculate the minimum time for the radio signal to travel from Earth to Mars.

Use the data in Table 19.1 and the equation: distance = speed × time

The average surface temperature on Earth is 15 °C.

Suggest whether the average temperature on Mars is higher or lower than 15 °C.

Use the data in Table 19.1 to explain your answer.

A student uses an electric heater to raise the temperature of water.

Fig. 20.1 shows some of the equipment the student uses.

The student obtains the data in Table 20.1:

Use the data in Table 20.1 to calculate the efficiency of the heater.

The heater is used for 5 minutes.

Calculate the power of the heater.

Use the data in Table 20.1 and the equation: energy transferred = power × time

* Explain how the student uses the equipment in Fig. 20.1 to obtain the data in Table 20.1.

In your answer you should:

• Include how any extra equipment is used.

• Explain how the quantities are calculated.

Two springs are used to make a catapult. The catapult is used to shoot a ball vertically upwards.

The diagram shows the ball and catapult at different stages:

At P the extension of each spring is 0.2 m.

The spring constant of each spring is 40 N / m.

Calculate the total elastic potential energy stored in the springs at P.

At Q the ball is released and has maximum kinetic energy. The springs have no extension at Q.

The kinetic energy of the ball at Q is less than the value of the elastic potential energy stored in the springs at P.

Explain why.

The springs are stretched to a new extension:

• The total energy stored in the two springs is 2.4 J.

• The mass of the ball is 0.050 kg.

• At R the ball reaches maximum height.

Calculate the maximum height reached by the ball.

Use the equation: potential energy = mass × height × gravitational field strength

A student investigates how the mass of the ball affects its speed at Q.

Describe one factor the student should control in their investigation.

A van travels along a road at a constant speed.

The van brakes and decelerates at a constant rate:

• The initial speed of the van is 18 m / s.

• The deceleration of the van is 1.5 m / s².

Calculate the time taken for the van to stop.

Use the equation: acceleration = change in velocity / time taken

The same van travels on an icy road at 18 m / s.

Explain how the stopping distance changes.

Write about thinking and braking in your answer.

If the van crashes, the time taken to stop is much smaller.

Explain why this is dangerous for the people in the van.

This question is about infra red (IR) and ultra violet (UV) radiation.

It took humans a long time to discover IR and UV radiation.

Suggest two reasons why.

Look at the information about some UV radiation:

• The wavelength of the UV radiation is 0.18 m.

• The wave speed of the UV radiation is 3.0 × 10⁸ m.

Calculate the frequency of the UV radiation.

Use the equation: wave speed = frequency × wavelength

Give your answer to 2 significant figures.

The ozone layer is part of the Earth’s atmosphere.

This graph shows how the percentage of UV radiation transmitted by the ozone layer depends on wavelength:

Describe the difference in the absorption of UV radiation at 0.31 m and 0.37 m.

Use data from the graph in your answer.

Why is the ozone layer important for humans on Earth?

Use the graph to help explain your answer.