4PH1/1P — November 2025 (Edexcel IGCSE Physics): Past Paper

This question is about stars.

The table gives information about four different stars. Mass in multiples of Star Colour Evolutionary stage the mass of the Sun Betelgeuse red 16.5 red supergiant Sirius A blue‑white 2.4 main sequence Sirius B white 1.0 white dwarf The Sun yellow 1.0 main sequence

Which of these stars has the lowest surface temperature?

Which of these stars will become a supernova in the future?

Sirius B and the Sun have approximately the same mass but are different colours and in different evolutionary stages. Describe two other differences between Sirius B and the Sun. 1 2

Sirius B orbits with Sirius A as part of a binary star system. The mean orbital radius of Sirius B is 29.7 × 10⁹ km. The time for Sirius B to complete one orbit is 50 years. Calculate the mean orbital speed of Sirius B. Give your answer in km / s. mean orbital speed = km / s

A car travels at a constant speed of 14 m / s along a road.

Calculate the distance travelled by the car in a time of 30 seconds. Use the formula distance travelled = average speed × time taken distance travelled = m

The driver of the car sees an obstacle in the road ahead and applies the brakes.

Which of these is a description of the thinking distance of the car? A distance travelled between applying the brakes and the car coming to a stop B distance travelled between seeing the obstacle and applying the brakes C distance travelled between seeing the obstacle and the car coming to a stop D distance travelled as the car slows down

Which of these factors would increase the braking distance of the car?

State the only factor that affects both the thinking distance and the braking distance of the car.

This is a simplified diagram of the electrical wiring in a house. 230 V a.c. circuit breaker circuit 6A 32 A breaker lights sockets

A current larger than 32 A flows in the sockets. Describe how having the circuit breaker in series with the sockets protects the house.

A student suggests that fuses could be used instead of the circuit breakers. Give two disadvantages of using fuses instead of circuit breakers. 1 2

Explain why the wiring in the house includes an earth wire.

The diagram shows a force pulling a block up a ramp. distance pulled along ramp = 3.7 m force = 120 N height lifted = 0.82 m

Show that the work done by the force is about 440 J. Use the formula work done = force × distance moved

The block gains 12 J of energy in its gravitational store when it is lifted through a height of 0.82 m. Calculate the mass of the block. mass = kg

A student states that most of the input energy is destroyed when the block is pulled up the ramp. Comment on the student’s statement.

This question is about radioactivity.

Uranium‑238 decays by emitting an alpha particle to become an isotope of thorium. Complete the equation for the alpha decay of uranium‑238. 238 U → 90 Th + α

The isotope of thorium produced in the decay of uranium‑238 is also radioactive. Thorium decays by emitting a beta particle. Describe how the structure of a thorium nucleus changes when a beta particle is emitted.

A teacher demonstrates radioactivity using a radioactive rock. The rock contains uranium‑238 and other radioactive isotopes. The teacher takes precautions to reduce the risk of contamination and irradiation by the radioactive rock.

Suggest a safety precaution that would reduce the risk of contamination by the radioactive rock.

Suggest a safety precaution that would reduce the risk of irradiation by the radioactive rock.

The teacher measures the amount of radiation emitted by the radioactive rock in a time of 1 minute using a Geiger‑Müller (GM) tube and counter. The teacher repeats this measurement to obtain a total of five measurements of the count rate. The table shows the teacher’s results. Count rate in counts per minute Calculate the mean count rate. Give your answer to 2 significant figures. . mean count rate = counts per minute

This question is about magnetism.

Diagram 1 shows the ends of two strong bar magnets and the space between the bar magnets. Diagram 1 There is a uniform magnetic field in the space between the bar magnets.

One of the magnetic field lines has already been drawn. Complete diagram 1 by drawing three more magnetic field lines and labelling the poles of the bar magnets.

Describe a method a student could use to show the shape and direction of the magnetic field between the bar magnets. You may draw a diagram to help your answer.

Name a magnetically soft material.

A student investigates how the length, L, of a current‑carrying wire in a magnetic field affects the size of the force on the wire. The student uses a power supply and keeps the current in the wire constant. They use the same magnet throughout the experiment. Diagram 2 shows part of the student’s equipment. connecting wire connecting wire N L S Diagram 2

Table 1 lists the variables in the student’s investigation. Add one tick (ü) to each row to show whether each variable is an independent, dependent or control variable. Variable Independent Dependent Control current length of wire in field force on wire magnetic field strength Table 1

Table 2 shows the student’s results. Length of wire in field Force in mm in N 0 0.00 5 0.32 10 0.64 15 0.92 20 1.28 25 1.58 30 1.92 Table 2 Plot a graph of the results on the grid.

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

Draw a line of best fit.

The student repeats the experiment but with a smaller current in the wire. Draw another line on the grid to show the expected results when using a smaller current.

The diagram shows an electric circuit used to determine the brightness of the light in a room. R

Add a voltmeter to the diagram to measure the voltage of resistor R.

State the formula linking voltage, current and resistance.

The voltage across resistor R is 1.9 V. The resistance of resistor R is 800 Ω. Calculate the current in the circuit. Give your answer in milliamps, mA. current = mA

Explain why the voltage across the light dependent resistor (LDR) decreases if the brightness of the light in the room increases.

Another resistor is connected in parallel with resistor R. The new resistor has a higher resistance than resistor R. Explain what happens to the current in the LDR in the circuit diagram. Assume that the brightness of the light in the room remains constant.

The diagram shows a pot made of clay. (Source: © Victoria Sergeeva / Shutterstock)

Describe a method that could be used to accurately determine the volume of clay used in the pot.

Give the name of a piece of apparatus that could be used to measure the mass of the clay pot.

The clay pot can be used to hold liquids. A student needs to determine the volume of liquid that can be contained in the pot. The student measures the mass of the empty pot and then measures the mass of the pot again when it is filled with a liquid. The table shows the student’s measurements. Mass of empty pot in kg 1.2 Mass of pot filled with liquid in kg 6.8 The density of the liquid used is 920 kg / m³. Calculate the volume of liquid that can be contained in the pot. Use the formula mass density = volume volume = m³

The photograph shows a car being driven along a straight race track. (Source: © Shayne T Wright/Shutterstock) The car starts from rest and accelerates along the straight race track. After crossing the finish line, the driver applies the brakes to bring the car to rest. The graph shows how the velocity of the car changes with time after the car starts to accelerate. 100 Q Velocity P in m/s R S 0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 Time in seconds

What feature of the graph gives the magnitude of the acceleration of the car?

At which point on the graph does the driver of the car first apply the brakes?

Explain why the graph is a curve for the first 11.0 seconds.

Calculate the distance travelled by the car from 11.0 seconds to 15.0 seconds. distance = m

This question is about light.

Light is an example of a wave. State what is meant by the term wave.

Diagram 1 shows a ray of light incident on a mirror. ray of light mirror Diagram 1 Draw another ray of light on diagram 1 to show the path of the ray after it is incident on the mirror.

Diagram 2 shows a ray of red light entering a semi‑circular glass block from the air. When the ray of red light is incident on the glass–air boundary, the light refracts with an angle of refraction of 90° air glass ray of red light Diagram 2

Using diagram 2, determine the critical angle for red light at the glass–air boundary. critical angle = degrees

Calculate the refractive index of the glass. refractive index =

The refractive index of blue light in glass is higher than the refractive index of red light in glass. A ray of blue light has an angle of incidence equal to the critical angle of the red light. Explain what would happen to the ray of blue light at the glass–air boundary.

The diagram shows apparatus that can be used to demonstrate convection currents. smoke tube A tube B candle The apparatus consists of a box with two tubes, A and B, that allow air to enter and leave the box. During the demonstration, a candle is placed inside the box directly underneath tube B. A source of smoke is placed above tube A. Using ideas about convection, explain why the smoke moves down into the box through tube A. You may add to the diagram to help your answer.

This question is about gas pressure.

Diagram 1 shows some gas particles contained in a box. Diagram 1

The gas particles move in random motion. State what is meant by the term random motion.

The gas exerts a pressure due to the gas particles colliding with the walls of the box. Explain how these collisions produce a pressure.

The volume of the box is increased but the temperature of the gas remains constant. Explain how increasing the volume of the box affects the pressure of the gas in the box. Assume the amount of gas remains constant.

Diagram 2 shows a device used to measure differences in gas pressure. This device is called a manometer. The difference between the pressure of the atmosphere and the pressure of the gas supply causes a difference in the height of the liquid levels on each side of the manometer. from atmosphere from gas supply height difference liquid Diagram 2

The liquid in the manometer is oil, which has a density of 820 kg/m³. The pressure difference between the atmosphere and the gas supply is 1850 Pa. Calculate the height difference between the liquid levels in the manometer. Use the formula pressure difference = height × density × gravitational field strength height difference = m

Different liquids can be used in the manometer. Liquid mercury has a density of 14 000 kg / m³. Suggest why liquid mercury would be more appropriate to use in the manometer when measuring very large pressure differences.

The pressure of a sample of gas is 232 kPa at a temperature of 16 °C. Calculate the temperature when the pressure of the sample of gas increases to 249 kPa. Give your answer in degrees Celsius (°C) Assume that the volume and the mass of the gas sample remain constant. temperature = ° C