Cambridge IGCSE Physics - 0625 - Core Paper 3 2019 Winter Zone 3

(a) A student uses a stopwatch in a timing experiment.

Fig. 1.1 shows the stopwatch readings.



Calculate the time interval between the two readings.

time interval = ........................................................... s [2]

(b) A device has a light-emitting diode (LED) that flashes briefly at regular intervals.

Describe how to determine accurately the average time for each interval, using a stopwatch.

..............................................................................................................
..............................................................................................................
..............................................................................................................
..............................................................................................................
.............................................................................................................. [4]

A student reviews some data about athletes and footballers.
(a) An athlete runs 12 km in 1.5 hours. Calculate the athlete’s average speed in km/h.

average speed = ........................................... km/h [3]

(b) Fig. 2.1 shows the speed-time graph for a footballer for the first 15.0 seconds of a game.



(i) Use the graph in Fig. 2.1 to calculate the distance travelled by the footballer during the first 4.0 seconds.

distance = ........................................... m [3]

(ii) Use the graph in Fig. 2.1 to determine when the footballer is moving with greatest acceleration.

Between .............................. s and ............................. s

Give a reason for your answer.

.........................................................................................................................................
.........................................................................................................................................

[2]
(c) Another footballer has a mass of 72 kg.

Calculate the weight of this footballer.

weight = ............................................ N [3]

A model aircraft is flying through air. Fig. 3.1 shows the forces acting on the model aircraft. The weight of the model aircraft is 15.0 N.



(a) (i) Determine the size and direction of the resultant horizontal force acting on the model aircraft.

size of resultant horizontal force = .......................................................... N
direction of resultant horizontal force = ..................................................... [1]

(ii) Describe the change in the motion of the model aircraft.
.............................................................................................................................................
............................................................................................................................................. [2]

(b) The horizontal forces acting on the model aircraft become balanced.
Suggest how the horizontal forces acting on the model aircraft have changed.
.............................................................................................................................................
............................................................................................................................................. [1]

(a) A man is working on a platform. He uses a rope to raise a bag from the ground to the platform as shown in Fig. 4.1.
[Image_1: Figure 4.1 showing a man, platform, rope, and bag]

(i) State the type of energy gained by the bag as it is lifted at constant speed.
....................................................................................................................................................... [1]

(ii) The man then lifts a second bag from the ground to the platform. The first bag weighs 100 N and the second bag weighs 150 N.
On which bag of materials does the man do more work?
.......................................................................................................................................................
Explain your answer.
.......................................................................................................................................................
....................................................................................................................................................... [1]

(iii) The man wants to determine his useful power as he lifts one of the bags. He knows the weight of the bag. State the two other quantities he needs to know.
1 ..................................................................................................................................................
2 .................................................................................................................................................. [2]

(b) The statements describe processes in a coal-fired power station. They are not in the correct order.
A Thermal energy boils water.
B Coal burns to produce thermal (heat) energy.
C Electricity is transmitted to a step-up transformer.
D A turbine turns coils in a magnetic field.
E Steam turns a turbine.

Use the letters A, B, C, D, and E to complete the flow chart explaining how the power station works.
[Image_2: Box diagram with 'Coal is crushed to a fine powder.' at the top and 'Electricity is generated.' at the bottom with empty boxes in between] [3]

(a) The arrows on Fig. 5.1 represent changes of state.
[Image_1: Diagram with solid, liquid, and gas states labeled with arrows numbered 1 to 4]
One of the arrows is labelled. Label each of the other arrows with the correct change of state.
Write the change of state on the dotted lines next to each arrow. [3]

(b) A beaker contains some liquid with a low boiling point. The beaker is placed onto a small amount of water, as shown in Fig. 5.2.
[Image_2: Diagram of beaker with labels for liquid with low boiling point, water on bench, and bench]
The liquid in the beaker evaporates quickly. The water on the bench cools and turns to ice.
Explain why the water cools. [3]

(a) Fig. 6.1 represents a transverse wave drawn full size. Point X represents a point on the wave.



(i) On Fig. 6.1, mark clearly the directions in which point X moves. [1]

(ii) Use Fig. 6.1 to measure the wavelength of the wave.

wavelength = ............................................... cm [1]

(iii) The frequency of the wave is increased. Describe how the wave pattern in Fig. 6.1 would be different.

..........................................................................................................................
.......................................................................................................................... [1]

(b) (i) Place a tick in a box next to any transverse wave.

[ ] light
[ ] sound
[ ] radio [1]

(ii) State a type of wave that cannot travel in a vacuum.

............................................................................................................................ [1]

(a) Complete the sentences. Add the missing word to each of the blank spaces.

The unit of temperature is called the ................................. .

The physical property that varies with temperature in a liquid-in-glass thermometer is the ................................. of the liquid.
[2]

(b) A student has a thermometer without a marked scale.
To produce a scale for the thermometer, the student must use two fixed points.
Give the temperature value for each fixed point and describe what happens to water at each of these temperatures.

Lower fixed point .............................................................................................................
.................................................................................................................................

Upper fixed point .............................................................................................................
.................................................................................................................................
[4]

Fig. 8.1 shows a ray of light travelling through a glass block and then reflecting from a mirror.


(a) State the term used for the dashed lines drawn in Fig. 8.1.
................................................................................................................................................................................... [1]

(b) Use Fig. 8.1 to identify the three angles in the list. Place the correct letter in the box to indicate each angle.

• [] angle of incidence
• [] angle of reflection
• [] angle of refraction

Two bar magnets are placed next to each other as shown in Fig. 9.1.

Magnet A is slowly moved towards magnet B. This causes magnet B to move away from magnet A.
(a) (i) On Fig. 9.1, suggest the poles of each bar magnet. Label N and S on each of the magnets. [1]
(ii) State the term used to describe the direction of the forces acting between magnet A and magnet B. [1]
(iii) Magnet B is removed and replaced with a steel bar of the same size. Describe what happens when magnet A is slowly moved towards the steel bar. [1]

(b) A student makes an electromagnet. He places an iron rod inside a coil of wire and connects the coil to a d.c. power supply, as shown in Fig. 9.2.

(i) The switch is closed so there is a current in the coil. The S pole of a bar magnet is placed near to each end of the iron rod in turn. Suggest what happens at each end of the iron rod and give a reason for your predictions. [2]
(ii) The student removes the iron rod from the coil. The student places a steel rod inside the coil. He closes the switch and the steel rod becomes a magnet. He then opens the switch. The student removes the steel rod and moves it close to the iron rod. Describe and explain what happens as the two rods are moved close together. [2]
(iii) State one use for an electromagnet. [1]

(a) State the name of the component shown in Fig. 10.1.
............................................................................................................................. [1]
(b) The resistance of the component shown in Fig. 10.1 varies with temperature. Fig. 10.2 shows a graph of resistance against temperature for the component.

(i) Use Fig. 10.2 to determine the resistance of the component at a temperature of 10 °C.
............................................................................................................................. Ω [1]
(ii) At another temperature, the resistance of the component is 800 Ω. Calculate the current in the component when it is connected to a 12.0 V supply.
current = .................................................. A [3]

Fig. 11.1 shows a diagram of an electrical device. The diagram is not complete. The coil rotates in a magnetic field when connected to a d.c. power supply.

(a) (i) Explain the meaning of the term d.c.
........................................................................................................
........................................................................................................ [1]
(ii) Complete the diagram in Fig. 11.1 by drawing the symbols for two cells in series and a switch to make a circuit. [2]

(b) (i) State the name of the electrical device shown in Fig. 11.1.
........................................................................................................ [1]
(ii) State two changes to the electrical device that will make the coil in the device rotate faster.
1. ........................................................................................................
2. ........................................................................................................ [2]

Fig. 12.1 shows the nuclide notation for three isotopes of an element.



(a) (i) Describe how the nuclide notation shows that each isotope is of the same element.
............................................................................................................................................
............................................................................................................................................ [1]

(ii) Describe how the nuclide notation shows the differences between the isotopes.
............................................................................................................................................
............................................................................................................................................ [1]

(b) Radioactive sources emit radiation when they decay. State the names of three types of radioactive emission.
1 .......................................................................................................................................
2 .......................................................................................................................................
3 ....................................................................................................................................... [2]

(c) Radioactive emissions have differing characteristics. One characteristic is their ionising effect.
Complete the statement about ionisation, using words from the box. The words can be used once, more than once or not at all.

[Table_1]

When atoms are ionised,
............................. may be removed, leaving ............................. charged atoms (ions), or
............................. may be gained, forming ............................. charged atoms (ions). [4]

(d) Polonium-210 has a half-life of 140 days. A sample of polonium-210 has 8.0 × 10¹⁰ atoms. Calculate the number of polonium-210 atoms remaining in the sample after 280 days.

number of atoms = ........................................................ [2]