Cambridge IGCSE Physics - 0625 - Core Paper 3 2023 Winter Zone 3

1. Fig. 1.1 shows the speed–time graph for a bus journey.

(a) Using the information in Fig. 1.1, determine:
(i) the maximum speed of the bus during the journey
maximum speed = .................................................. m / s [1]
(ii) the speed of the bus at time = 65 s. On Fig. 1.1, show how you obtained this information.
speed = .................................................. m / s [2]
(b) Describe how the speed of the bus changes between time = 60 s and time = 80 s.
...................................................................................................................................................
............................................................................................................................................. [2]
(c) Determine the distance travelled by the bus between time = 0 and time = 10 s.
distance travelled = ......................................................m [3]
(d) Fig. 1.2 shows the speed–time graph for another bus journey. The driver sees a hazard ahead and applies the brakes at time = 40 s. The bus reduces its speed from 14.0 m / s to 6.0 m / s in a time of 5.0 s. On Fig. 1.2, draw the speed–time graph for the bus as it reduces its speed. [2]

2. A farmer uses a rope to lift a barrel of fruit from the ground to a platform, as shown in Fig. 2.1.

(a) The farmer lifts the barrel of fruit at a constant speed.
(i) State the energy store of the barrel of fruit that increases as the barrel rises.
..................................................................................................................................... [1]
(ii) The weight of the barrel of fruit is 140 N. Show that the work done on the barrel of fruit in lifting it from the ground to the platform is approximately 450 J. [2]
(b) The farmer wants to make the process faster. He buys a machine to lift the barrels of fruit.
(i) The output power of the machine is 75 W. The work done in lifting a barrel of fruit onto the platform is 450 J. Calculate the time taken for the machine to lift a barrel of fruit onto the platform.
time = ....................................................... s [3]
(ii) The machine uses an electric motor. The farmer installs some wind turbines to supply electrical power for the farm. Suggest one environmental reason for using wind turbines rather than using a diesel (fossil fuel) generator.
...........................................................................................................................................
..................................................................................................................................... [1]

3. The mass of a glass bottle is 0.18 kg.
(a) Calculate the weight of the bottle.
weight = ...................................................... N [2]
(b) The bottle contains 2.7 kg of cooking oil. The density of the cooking oil is 0.92 g / cm³. Calculate the volume of the cooking oil.
volume = .................................................. cm³ [4]
(c) A cookery student pours some cooking oil into a glass bowl containing water, as shown in Fig. 3.1.

The student accidently drops a plastic spoon and a metal spoon into the bowl. The densities of the spoons and liquids are shown in Table 3.1.
[Table_1]
On Fig. 3.1, label a suggested position for each spoon after each has fallen into the bowl. Use the letter P to label the position of the plastic spoon and the letter M to label the position of the metal spoon. [2]

4. (a) Fig. 4.1 shows a pan on a hotplate. The hotplate heats the pan and the water.

Use your ideas about thermal energy transfer to explain why the pan has:
(i) a wooden handle
..................................................................................................................................... [1]
(ii) shiny sides
...........................................................................................................................................
..................................................................................................................................... [2]
(iii) a copper base.
..................................................................................................................................... [1]
(b) Fig. 4.2 shows a heater for warming a room. When there is hot water in the heater, thermal energy transfers from the water to the room.

Explain how thermal energy from the heater warms the entire room. Use your ideas about the density of air. You may draw on Fig. 4.2.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]

5. (a) Fig. 5.1 shows regions of the electromagnetic spectrum in order of increasing wavelength. Two of the regions are unlabelled.

(i) Complete Fig. 5.1 by writing the name of each unlabelled region in the correct box. [2]
(ii) State two properties that are the same for all regions of the electromagnetic spectrum.
1........................................................................................................................................
...........................................................................................................................................
2........................................................................................................................................
...........................................................................................................................................
[2]
(b) (i) State one use for infrared radiation.
..................................................................................................................................... [1]
(ii) State one harmful effect of excessive exposure to infrared radiation.
..................................................................................................................................... [1]

6. (a) A student shines a ray of red light into a rectangular glass block, as shown in Fig. 6.1.

(i) Draw the normal at the point where the ray of red light enters the glass block. [1]
(ii) On Fig. 6.1, label each ray using words from the list: diffracted, diffused, dispersed, incident, reflected, refracted. [2]
(b) Fig. 6.2 and Fig. 6.3 each show two parallel rays of light travelling through air towards a lens. For each lens, draw the path of the two rays as they pass through the lens and back into the air. [2]
(c) State the seven colours of visible light. Give the colours in order of frequency. [2]

7. Two identical resistors, R1 and R2, are connected to a 24 V battery, as shown in Fig. 7.1.

The value of each resistor is 50 Ω.
(a) Calculate the combined resistance of R1 and R2 when they are connected as shown in Fig. 7.1.
combined resistance = ...................................................... Ω [1]
(b) Show that the current in the circuit is approximately 0.25 A. [3]
(c) Determine the potential difference (p.d.) across R1.
p.d. = ....................................................... V [1]
(d) Calculate the power transferred in R1.
power = ..................................................... W [3]
(e) A student connects R1, R2 and the battery to make a different circuit. The resistors R1 and R2 are connected so their combined resistance is as small as possible. Draw a circuit diagram to show how R1 and R2 are connected to the battery. [1]

8. (a) Fig. 8.1 shows an arrangement for transmitting electricity generated by a power station.

The step-up transformer has 500 turns on the primary coil. Calculate the number of turns on the secondary coil of the step-up transformer. Use the information given in Fig. 8.1.
number of secondary turns = ......................................................... [3]
(b) State two benefits of using high voltages for transmitting electricity.
1................................................................................................................................................
2................................................................................................................................................
[2]

9. (a) Describe what is meant by alternating current (a.c.).
............................................................................................................................................. [1]
(b) A teacher demonstrates how a loudspeaker works by using the equipment shown in Fig. 9.1.

There is an alternating current in the coil. The paper cone and coil vibrate as shown in Fig. 9.1.
(i) Explain why the paper cone vibrates. Use your ideas about magnetism.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(ii) When the paper cone vibrates, the teacher hears a sound. Suggest a value for the frequency of the alternating current. Include the unit.
frequency = ...............................................................
unit ............................................................... [2]

10. (a) Fig. 10.1 represents all the particles in a lithium atom.

(i) State the proton number (atomic number) of the lithium atom in Fig. 10.1.
..................................................................................................................................... [1]
(ii) Determine the nucleon number (mass number) of the lithium atom in Fig. 10.1.
nucleon number = ......................................................... [1]
(iii) Describe how a lithium atom changes to form a positive ion.
..................................................................................................................................... [1]
(b) The half-life of iodine-131 is 8 days. A sample contains 80 mg of iodine-131. Calculate the time taken to decay until 10 mg of iodine-131 remain in the sample.
time taken = ................................................. days [2]

11. Fig. 11.1 represents the Earth in orbit around the Sun.

(a) (i) State the name of the force that keeps the Earth in orbit around the Sun.
..................................................................................................................................... [1]
(ii) State the time taken by the Earth to complete one orbit of the Sun. Include the unit.
time for one orbit = ......................................................... [1]
(iii) State the time taken by the Earth to rotate once on its axis. Include the unit.
time for one rotation = ......................................................... [1]
(iv) The Sun consists mainly of two gases. State the names of the two gases.
............................................................... and ............................................................... [2]
(b) (i) Most of the radiation from the Sun consists of visible light and two other regions of the electromagnetic spectrum. State the name of one of the other two regions.
..................................................................................................................................... [1]
(ii) The speed of visible light is 3.0 × 10⁸ m/s. Calculate the time taken for visible light to travel from the Sun to the Earth when the Earth is in the position shown in Fig. 11.1.
time taken = ....................................................... s [3]