Cambridge IGCSE Physics - 0625 - Core Paper 3 2018 Summer Zone 1

Model trains move along a track passing through two model stations. Students analyse the motion of a train. They start a digital timer as the train starts to move. They record the time that it enters Station A and the time it enters Station B.

Fig. 1.1 shows the time on entering Station A and the time on entering Station B.



(a) Calculate the time taken from the train entering Station A to the train entering Station B. State your answer in seconds.

time taken = .................................................... s [1]

(b) A faster train takes 54 s to travel from Station A to Station B. The distance between the stations is 120 m.

Calculate the average speed of this train.

average speed = .................................................... m/s [3]

(c) Fig. 1.2 shows the speed-time graph for a train travelling on a different part of the track.



Determine the total distance travelled by the train on this part of the track.

distance = .................................................... m [4]

(a) (i) A student has a measuring cylinder and a balance.
Describe an experiment to determine the density of the liquid.

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(ii) Suggest the unit of density used by the student.
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(b) Fig. 2.2 shows a block of polythene.

(i) Polythene floats in water. Explain why polythene floats.
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(ii) The weight of the polythene block is 0.84 N.
Calculate the mass of the block.
mass = ........................................ kg [3]

(a) Fig. 3.1 shows the vertical forces on a rocket.

Calculate the resultant force on the rocket.
resultant force = ..................................................... N
direction = ...............................................................[3]
(b) Fig. 3.2 shows the speed and direction of motion of an object at a point in time.

The resultant force on the object is zero for 10 seconds.
Deduce the speed and direction of motion after 5 seconds. Indicate the speed and direction
of the object by drawing a labelled arrow next to the object in Fig. 3.3.

(a) Fig. 4.1 shows a smoke cell. The cell contains smoke particles and air molecules. It is lit from the side. A student views the motion of smoke particles in the cell by using a microscope.



Fig. 4.1

Describe and explain what the student sees when viewing the smoke particles through the microscope.
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(b) Drops of water on a warm surface disappear after a short time. State the term used to describe this process. Explain the process, using your ideas about molecules.

name of process ...............................................................................................
explanation ...............................................................................................
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(a) In a geothermal power station, the process of generating electricity includes seven stages. Four of the stages are shown below.

P steam turns a turbine
Q hot underground rocks heat the cold water
R the turbine spins a generator
S hot water rises to the surface

The flow chart in Fig. 5.2 shows the seven stages, but it is incomplete. Complete the flow chart by adding the letters P, Q, R and S in the correct sequence.

[Image_1: Fig. 5.1 includes a diagram of a generating station with cold water pumped down and hot water rising to the surface.]

[Image_2: Fig. 5.2 is a flow chart with the labels: cold water is pumped down, hot water produces steam, electricity is generated.]

(b) The cost of electrical energy obtained from a geothermal power station is similar to the cost of electrical energy obtained from wind turbines.

Describe one advantage and one disadvantage of using a geothermal power station to generate electricity compared with using wind turbines.

advantage ...............................................................................................................................
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disadvantage ............................................................................................................................
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A student constructs a device for absorbing thermal energy from the Sun. Fig. 6.1 shows the device.

The student places the white plastic pipe in sunlight. The cold water flows slowly from Tank A to Tank B. Energy from the Sun heats the water in the pipe.
Fig. 6.2 shows the temperatures in Tank A and Tank B.

(a) Determine the rise in temperature of the water.
temperature rise = ...................................................°C [1]
(b) The student wants to increase the thermal energy absorbed by the water in the pipe. Suggest three improvements he can make to increase the thermal energy absorbed.
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[3]
(c) Describe how the thermal energy is transferred from the Sun to the water inside the pipe.
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[2]

The spectrum of white light is made up of seven colours.
(a) Fig. 7.1 shows a partially-completed spectrum. Two labels are missing.

(i) On Fig. 7.1, write the name of the missing colour in each blank space. [2]
(ii) On Fig. 7.1, indicate the direction of \textbf{increasing} wavelength for the spectrum. Draw an arrow in the box below the spectrum of colours. [1]
(b) A ray of red light strikes one face of a triangular glass prism as shown in Fig. 7.2.

(i) On Fig. 7.2, draw the path of the ray as it travels through the glass prism and enters the air. [2]
(ii) State the term used to describe what happens to the ray of red light as it enters and leaves the prism. ............................................................. [1]

This question is about measuring the speed of sound in air.
A student stands in front of a large wall. She hits a drum and hears an echo. Fig. 8.1 shows the position of the student and the wall.



(a) (i) State the name of a piece of equipment for measuring the distance from the student to the wall.
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(ii) Explain how sound forms an echo.
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(b) The student hits her drum repeatedly once per second. She walks away from the wall and listens for the echo. When the student is 170 m from the wall she hears the echo from one beat of the drum at the same time as the next beat of the drum.

Use this information to determine the speed of sound. State the unit.

speed = .......................................................... [4]

(a) (i) On Fig. 9.1, add the names of the missing radiations at A and at B. [2]
(ii) Indicate the radiation that has the lowest frequency. On Fig. 9.1, draw a ring around the radiation. [1]
(b) State two safety precautions when handling sources that emit gamma radiation.
1 .................................................................................................................................
2 ................................................................................................................................. [2]
[Image_1: Fig. 9.1 shows a partially-labelled diagram of the electromagnetic spectrum.]

(a) On Fig. 10.1, label the fixed resistor, by writing the letter R. [1]

(b) Two components in Fig. 10.1 measure electrical quantities. Identify the quantity that each component measures. Write each quantity and the unit of each quantity in the correct place in Table 10.1.

[Image of Table 10.1]

component: A, quantity: ext{.....................}, unit: ext{.....................}
component: V, quantity: ext{.....................}, unit: ext{.....................}
[4]

(c) A student uses the circuit in Fig. 10.1 to determine the resistance of wires made from the same material. State how the resistance of a wire is related to its length and its diameter.

length .......................................................................................................
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diameter ....................................................................................................
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(a) (i) On Fig. 11.1, draw a cell and a switch in series with the conductor to form a complete circuit. Use the correct circuit symbols. [2]
(ii) A student sprinkles iron filings onto the card and closes the switch. There is a current in the conductor. Describe the pattern of the magnetic field seen. .............................................................................................................................................................. .............................................................................................................................................................. [2]
(iii) The student reverses the direction of the current in the conductor. State the effect, if any, on the pattern he sees. .................................................................................................................................................................................................... [1]


(b) Describe an experiment to show that a force acts on a current-carrying conductor in a magnetic field. Show how to arrange the equipment. Include a diagram in your answer. .............................................................................................................................................................................................................................................................................................................................................................................................................................. [4]

Radioactive decay may include the emission of:

α-radiation
β-radiation
γ-radiation

(a) (i) From the list, state the type of radiation which has the greatest ionising effect.
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(ii) From the list, state the type of radiation which has the lowest penetrating ability.
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(b) In a factory, rollers press aluminium metal to make thin foil sheets. An automatic system for controlling the thickness of the foil uses a radioactive source. The automatic system changes the gap between the top and bottom roller. Fig. 12.1 shows the equipment.



(i) Use your ideas about the properties of radiation to suggest and explain the type of radiation used.
type of radiation .........................................................................................................................
explanation ..............................................................................................................................
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(ii) The aluminium foil passing the radiation detector is too thin. Describe how this fault affects the reading on the counter.
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(iii) Suggest how the fault in (b)(ii) is corrected. State what happens to the rollers.
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(iv) The source used is strontium-90. A nucleus of strontium-90 can be described as $^{90}_{38} \text{Sr}$. State the number of protons in a nucleus of strontium-90.
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