4PH1/1P — January 2020 (Edexcel IGCSE Physics): Past Paper

The passage describes some of the properties of magnets and magnetic fields. Use words from the box to complete the passage. aluminium copper hard negative north positive soft south steel Each word may be used once, more than once or not at all. The north pole of one magnet will repel the pole of another magnet. There is attraction between and magnets. Materials that are difficult to magnetise are called magnetic materials. The direction of the magnetic field lines for a magnet is from to south. Iron is a magnetic material.

A ship floats on the sea. upthrust surface of sea

The ship floats because of the forces acting on it.

The upward force acting on the ship is called upthrust. This force is shown on the diagram. Draw another labelled arrow on the diagram to show the other vertical force acting on the ship.

Forces are vector quantities. State what is meant by the term vector quantity.

Give another example of a vector quantity.

The upthrust force acting on the ship is proportional to the pressure difference between the bottom of the ship and the surface of the sea. The pressure acting on the ship at the surface of the sea is 100 kPa.

State the formula linking pressure difference, height, density and gravitational field strength (g).

The bottom of the ship is 15.8 m below the surface of the sea. Show that the pressure acting on the bottom of the ship is approximately 260 kPa. [density of seawater = 1030 kg/m³]

Explain why the bottom of the ship is deeper below the surface of the sea when the ship is fully loaded with cargo.

This question is about electric circuits.

Which quantity is defined as the rate of flow of charge?

Which quantity is defined as the energy transferred per unit charge passed?

Diagram 1 shows an electric circuit with two resistors, R and S. Some of the values of the current are also shown. 0.60 A A2 0.40 A R A1 S Diagram 1

On Diagram 1, draw a voltmeter to measure the voltage of resistor S.

Deduce the readings on the ammeters. current measured by A₁ = A current measured by A₂ = A

Resistor R has a resistance of 11 Ω. Calculate the voltage across resistor R. voltage = V

Explain how the voltage across resistor R compares with the voltage across the battery.

Diagram 2 shows a different circuit containing a battery, an ammeter and a thermistor. A Diagram 2 Explain how the thermistor can be used to vary the current in this circuit.

A student investigates how much pressure she exerts on the ground when she is standing up.

The weight of the student is 520 N.

State the formula linking weight, mass and gravitational field strength (g).

Calculate the mass of the student. mass = kg

The student measures the area of one of her feet when it is in contact with the ground. She draws around her foot on a piece of squared paper. grid not to scale 2 cm 2 cm

The squares on the paper have a side length of 2 cm. Estimate the area of the student’s foot in contact with the ground. area = cm²

State the formula linking pressure, force and area.

The weight of the student is 520 N. Calculate the pressure the student exerts on the ground when she is standing on both feet. Give the unit. pressure = unit

A bus transports passengers. © Mikbiz/Shutterstock

The bus stops at certain points in its journey to let passengers get on or off the bus. The distance-time graph shows part of the bus journey, with sections labelled A to G. 8.0 6.0 G F E D Distance 4.0 in km C 2.0 B A 0.0 0 2 4 6 8 10 12 14 Time in minutes

Give the letters of the sections where the bus is stationary.

Calculate the speed of the bus during section C of the journey. Give your answer in m / s. speed = m / s

Explain what the graph shows about the speed of the bus in section E compared with the speed of the bus in section A.

Another bus travels a distance of 7.0 km in a time of 14 minutes. This bus travels at a constant velocity. Complete the velocity-time graph to show the motion of this bus. 0.6 0.4 Velocity in km / minute 0.2 0.0 0 2 4 6 8 10 12 14 Time in minutes

A teacher makes a hot drink. He puts the drink in a cup designed to keep the drink hot. The photograph and cross-section diagram both show the cup. plastic lid vacuum shiny metal outer surface shiny metal inner surface Explain how the design of the cup keeps the drink hot. Refer to methods of energy transfer in your answer.

A student uses a syringe containing trapped air to investigate pressure. Diagram 1 shows the apparatus he uses. pressure gauge syringe trapped air piston Diagram 1

Diagram 2 shows the pressure gauge when the piston is at its initial position. 20 40 10 50 kPa 0 60 © Lubos Chlubny/Shutterstock Diagram 2 Determine the reading on the pressure gauge. pressure = kPa

The piston is pushed in so that the volume of trapped air in the syringe is halved. The temperature of the trapped air remains constant. Explain how the reading on the pressure gauge will change when the piston is pushed in.

The position of the piston is then fixed so that the volume of trapped air in the syringe is now constant. The air in the syringe is then cooled.

State how the motion of air particles inside the syringe changes when the air is cooled.

Explain how the pressure of the trapped air inside the syringe changes when the air is cooled. Refer to particles in your answer.

A car is moving along a road.

The car has an initial velocity of 26 m / s. The car then accelerates at 1. 2 m / s2 until it reaches a velocity of 35 m / s.

State the formula linking acceleration, change in velocity and time taken.

Calculate the time taken for the car to accelerate to 35 m/s. time = s

A radar speed gun is used to measure the speed of the moving car. © Petar An/Shutterstock The radar speed gun emits radio waves towards the moving car. The moving car reflects the radio waves back to a detector on the gun. The detected radio waves have a different frequency from the emitted radio waves. This change in frequency is used to measure the speed of the moving car. Explain this change in frequency when the car is moving towards the radar speed gun.

A teacher investigates the penetrating ability of the gamma rays from a gamma source. This is the teacher’s method.

• place the gamma source at a distance of 25 cm from a radiation detector
• place a 1 cm thick absorbing material between the source and the detector
• measure the radiation count from the source for a time period of 3 s
• calculate the count rate in counts per second
• repeat the measurement two more times The teacher repeats this method for different absorbing materials.

Name a suitable radiation detector that the teacher could use.

State the independent variable in the teacher’s investigation.

Explain why every absorbing material used in the investigation has a thickness of 1 cm.

Suggest one improvement the teacher could make to this method.

The table shows the teacher’s results for seven different absorbing materials. Count rate in counts per second Absorbing material Test 1 Test 2 Test 3 Mean plastic 248 230 226 235 copper 138 127 147 137 wood 226 231 224 227 aluminium 204 211 190 202 lead 96 102 92 97 glass 204 192 190 195 stone 205 200 205 203

On the grid, plot a bar chart of the mean count rate for each absorbing material.

Why is a bar chart the correct way to display the results?

A student concludes that plastic is the best absorber of gamma radiation because plastic gives the largest mean count rate. Evaluate the student’s conclusion.

This question is about light.

Diagram 1 shows a light ray entering a glass prism. X B air 40° glass prism A light ray Y Diagram 1

Describe what happens to the light ray when it enters the prism at point A.

State the name of line XY.

State the formula linking critical angle and refractive index.

The refractive index for the glass in this prism is 1.6 Calculate the critical angle for the glass in this prism. critical angle = °

Complete Diagram 1 by continuing the path of the light ray from point B.

Diagram 2 shows a similar prism that is made from a material with a different refractive index. The critical angle for the material of this prism is 55° Complete Diagram 2 by continuing the path of the light ray. air 40° light ray Diagram 2

Technetium-99m is an isotope of the element technetium.

Technetium-99m has a half-life of 6 hours. A sample of technetium-99m has an initial activity of 160 Bq. Complete the graph to show how the activity of this sample of technetium-99m changes over a period of 24 hours. 200 150 Activity 100 in Bq 0 5 10 15 20 25 Time in hours

Technetium-99m has a half-life of 6 hours and can be used as a medical tracer. It is injected into a patient’s blood and moves around the patient’s body. Technetium-99m emits gamma radiation, which is used to locate the position of the tracer in the patient’s body.

Technetium-99m does not exist naturally. Suggest why technetium-99m is usually made at the hospital where it is used.

Explain why technetium-99m is an effective isotope to use as a medical tracer.

The gamma radiation emitted by technetium-99m is potentially harmful to humans. Discuss the risks of using technetium-99m to doctors and to patients.

The planets Mars and Saturn orbit around the same star, the Sun.

The diagram shows the orbital paths of Mars and Saturn. Not to scale Saturn Sun Mars Draw an orbital path of a comet on the diagram.

The table gives some information about the orbits of Mars and Saturn. Mars Saturn Orbital radius in km 2.28 × 10⁸ 1.43 × 10⁹ Orbital speed in km/s 24.1 9.70 Mars completes a number of orbits in the time it takes for Saturn to complete one orbit. Calculate the number of orbits that Mars completes in the time it takes for Saturn to complete one orbit. number of orbits =