Igcse e Electricity With Msc

8/9/2019 Igcse e Electricity With Msc

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IGCSE EDEXCEL

ELECTRICITY

4 Some students are investigating a simple electric motor.

(a) When the switch is closed the coil spins on the axle. State why.

(2)

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(b) State two changes that would make the motor spin faster.

(2)

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2 .........................................................................................................................................

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(c) The students change their circuit, replacing the cell and switch with a lamp.


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When they spin the coil by hand, the lamp lights. Explain why the lamp lights.

(2)

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(Total for Question 4 = 6 marks)

10 A student investigates how the resistance of a thermistor changes with temperature.

He measures a current and a voltage. The diagram shows part of the circuit that the

student uses.


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(a) (i) Label the thermistor on the diagram.

(1)

(ii) Add to the diagram to show how a voltmeter should be connected.

(2)

(b) The student varies the temperature of the thermistor and obtains the results below.

Temperature in °C 0 20 40 60 80 100

Current in mA 0.8 2.0 4.2 8.2 15.1 26.6

(i) State the equation linking voltage, current and resistance.

(1)

(ii) The voltage across the thermistor is 12 V.


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Calculate the resistance of the thermistor at 20 °C.

(2)

Resistance = .............................. Ω

(iii) Use the results from the table opposite to plot a graph of current against

temperature.

(5)

(iv) Use your graph to describe how the current in the thermistor changes as the

temperature increases.

(2)

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(v) The student concludes:

Evaluate this conclusion.

(2)

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3 The photograph shows a worker fuelling an aircraft.

Fuelling an electrically-charged aircraft can be dangerous. The worker connects a safety

wire to the aircraft before adding the fuel.

(a) Explain how an aircraft can become electrically charged while it is flying.

(2)

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(b) Describe a possible danger of fuelling an electrically-charged aircraft.

(1)

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(c) What electrical connection is made by the safety wire?

(1)

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(d) Explain how connecting the safety wire reduces the possible dangers when fuelling

an electrically-charged aircraft.

(2)

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2. (a) One of the building blocks of communication systems is the transducer.

(i) Name two other building blocks.

1 .............................................................................................................................

2 .............................................................................................................................

(2)

(ii) Explain the function of a transducer.

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

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

(2)

(b) The block diagram shows the sound system for a concert hall.

(i) The performance can be recorded


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using a digital system or an analogue system.

Give one example of the type of storage used in each system.

digital .....................................................................................................................

analogue .................................................................................................................

(2)

(ii) The diagram shows a loudspeaker.

Explain how the loudspeaker works.

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(4)

(Total 10 marks)

2. (a) (i) Any two from:1. encoder;2. modulator;

3. decoder / demodulator;4. storage;


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5. transmitter;6. amplifier;7. receiver

(ii) An explanation to include:1. change energy / signal;2. from one form to another;[Or specific example viz sound signal to electrical signal]

(b) (i) digital - CD / mp3 player / ipod / hard drive / memory stick /chip etc; analogue - vinyl record player / magnetic tape / tape recorder / tape /cassette recorder / record;

(ii) An explanation to include three from:1. current in coil;2. produces magnetic field;3. fixed magnetic field;

4. force produced on coil / coil moves;5. alternating current in coil / moves backwards;6. changing magnetic field in coil;7. relating movement diaphragm to producing sound (detail needed);plus one communication mark for ensuring that spelling, punctuationand grammar are accurate, so that the meaning is clear

Total 10 marks

6. The diagram shows part of a cathode ray oscilloscope (CRO).

(a) Explain how the electron gun produces a beam of electrons.

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(4)

(b) An alternating voltage is connected to the CRO. The time base is switched on. The

diagram shows the trace on the screen.

The vertical scale is set at 5 V/cm. The time base setting is 10 ms/cm.

(i) Use this information and the diagram to calculate the maximum value of the

alternating voltage

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(2)

the frequency of the alternating voltage.

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(3)

(ii) The time base is switched off. Draw the new trace on the diagram above.


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(1)

(Total 10 marks)

6. (a) An explanation to include three from:1. accelerated by anode / attracted / pulled across / OWTTE;

2. heated filament / hot cathode / OWTTE;3. electrons boiled off / electrons emitted / thermionic emission;plus one communication mark for using a suitable structure and style ofwriting (two linked ideas)

(b) (i) the maximum value of the alternating voltage3 x 5 ;= 15;[If 30(V) – 1 mark only]the frequency of the alternating voltage7 x 10 or 7 x 0.01;

1/their time

14.3 Hz;

(ii) straight vertical line on trace;

Total 10 marks

2. (a) Electrical heating is used in different ways, for example in an electric kettle.

Give two other examples of devices which use electrical heating.


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1 ....................................................................................................................................

2 ....................................................................................................................................

(2)

(b) Electricity can be dangerous. Safety features such as fuses are often used. Give two

other examples of electrical safety features.

1 ....................................................................................................................................

2 ....................................................................................................................................

(2)

(c) Explain why it is dangerous to touch an electric socket when your hands are wet.

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(2)

(d) A small object is stuck in an electric socket. Explain why it is dangerous to use a

metal screwdriver to remove it.

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(2)

(Total 8 marks)


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8. Use words from the box to complete the sentences. You may use each word once,

more than once or not at all.

Attraction electrons friction gravity metals

neutrons plastics protons repulsion

Materials which do not conduct electricity, such as .............................. are known as

insulators. They may be charged by ...............................

Positive charge on a material is due to .............................. being removed from its

surface and negative charge is due to .............................. being added to its surface.

The forces between unlike charges are forces of ...............................

(Total 5 marks)

10. A circuit contains a resistor R , a thermistor and a buzzer connected to a cell as

shown. The circuit can be used as a simple fire alarm.

(a) (i) Complete the sentence.


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When temperature increases, the resistance of a thermistor ........................................

(1)

(ii) What happens to the current in the circuit when the temperature increases?

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

(1)

(b) (i) State the equation which relates voltage, current and resistance.

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

(1)

(ii) When temperature increases, does the voltage across R stay the same, increase or

decrease?

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(1)

(iii) Explain your answer.

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

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(2)

(c) The buzzer starts to sound when the voltage across R is a particular value. Add a

voltmeter to the circuit diagram to show how this voltage is measured.

(1)

(Total 7 marks)


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15. (a) The diagram shows a step-up transformer.

(i) Calculate the value of the output voltage.

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Output voltage = ............................ V

(3)

(ii) Is the output voltage a.c. or d.c.?

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

(1)

(b) The diagram below shows an electricity generation and transmission system. Step-

up and step-down transformers are used.

On the dotted lines label these transformers U (step-up) or D (step-down).

(1)


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2. (a) The diagram shows the inside of a three-pin plug.

The cable is secured by the grip so that it cannot be pulled out of the plug. Use words

from the box to complete the sentences.

frayed high long thick

(i) Cables connected to plugs should not be too ........................................................

(1)

(ii) They should also not be .........................................................................................

(1)

(b) Describe the fault in the wiring of this plug.

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(1)


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(c) A plug is fitted with a 5 A fuse and connected to a small radio with a plastic casing.

Explain

(i) why an earth wire is not needed,

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(1)

(ii) why the fuse is unlikely to blow.

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(1)

(d) Fuses and earth wires provide protection when faults develop in electrical

equipment.

Name one other electrical safety device.

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(1)

(Total 6 marks)

11. A student connects a light dependent resistor (LDR) to a battery.

(a) The current in the LDR is 0.050 A and its resistance is 90 Ω in the dark.

(i) State the equation which relates current, resistance and voltage.

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(1)

(ii) Calculate the voltage across the LDR. Show your working and give the unit.

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Voltage = ..................................................

(2)

(b) The LDR is moved to a position in the light. Choose words from the box to

complete the table. You may use each word once, more than once or not at all.

Effect on … It will …

the resistance of the LDR

the current in the LDR

(2)

(Total 5 marks)

12. (a) The diagram shows how a student

connects several components in a circuit. The student uses four identical 1.5 volt cells.

Decrease increase stay the same


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(i) Identify component Y.

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(1)

(ii) The reading on ammeter Z is 50 mA.

What is the reading in milliamps on each of the other two ammeters?

ammeter W = ......................... mA ammeter X = ......................... mA

(1)

(iii) The student expected the lamp to be brighter and the reading on the voltmeter to be6.0 V.

The voltmeter is working correctly.

Give two reasons why the reading on the voltmeter is less than 6.0 V.

1 .............................................................................................................................

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

(1)

2 .............................................................................................................................

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(1)

(b) The graph shows how the current in a filament lamp varies with the voltage across

it.


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Explain why the graph is not a straight line.

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(3)

(Total 7 marks)

14. (a) When you rub a polythene rod with a

woollen cloth the rod becomes negatively charged.

(i)

Complete the labels on the diagram.


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(1)

(ii) Explain why the polythene rod then remains negatively charged for some time.

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(2)

(iii) If you rub a copper rod rather than a polythene rod, the copper rod will not staycharged. Why not?

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(1)

(b) Complete the following.

When a petrol tanker is filled or emptied the build-up of charge can be dangerous.

This is because a ........................................ may occur and this can ignite the petrol

vapour and cause an explosion.

(1)

(Total 5 marks)


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3. The diagram shows a small screwdriver.

(a) (i) Which part, or parts, can conduct electricity easily? Put a cross (☒) next to the

correct answer.

□ both parts

□ neither part

□ only the blade

□ only the handle

(1)

(ii) A child pushes the screwdriver into a mains electricity socket. This is very

dangerous. Why?

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

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(1)

(b) Give an example of one device in the home in which electrical heating is used.

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(1)

(c) The diagram shows one kind of fuse.


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(i) Electricity passes from one end of the fuse to the other. What path does it take?

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(1)

(ii) When there is a current in the fuse a transfer of energy takes place. Complete the

boxes for this transfer.

(2)

(iii) Complete the sentence by putting a cross in the correct box. When the current

increases, the temperature of the fuse will

□ decrease

□ increase

□ stay the same

(1)

(iv) Explain why fuses are used.

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

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(2)

………….

Energy →

……….

energy


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(Total 9 marks)

6. A student uses a set of LEDs (light emitting diodes) to make a sign. Her sign can be

used to show different messages. The diagram shows FIRE EXIT as an example.

(a) (i) Are the LEDs connected in series or in parallel?

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

(1)

(ii) Explain.

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(1)

(b) There is only a very small current in each lit LED. Which unit is used for this

current? Put a cross in the correct box.

□ mA

□ mC


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□ mΩ

□ mV

(1)

(c) Each LED lets charge flow in only one direction. A direct current (d.c.) gives a flow

of charge in only one direction.

(i) Which word in the box means the ‘rate of flow of charge’?

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

(1)

(ii) Give an example of a d.c. supply.

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(1)

(d) What does the abbreviation a.c. mean?

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(1)

(Total 6 marks)

14. A class uses a step-up transformer in a model transmission line. The transformer is

shown below. The input voltage is 6 Va.c. and there are 20 primary turns.


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(a) The output voltage is 24 Va.c. How many secondary turns does the transformer

have?

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Number of turns = ............................

(2)

(b) State how this transformer could be used as a step-down transformer.

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(1)

(c) A student wants to use an input voltage of 60 Va.c. Why does the teacher tell him

that this is not a good idea?

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(1)

(d) A step-up transformer is used just outside a power station to increase the voltage.

State why the voltage is increased.

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(1)

(Total 5 marks)


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15. In electrostatic paint spraying, the surface being painted is given a negative charge.

The paint emerges from the paint sprayer carrying a positive charge.

(a)

The diagram shows a metal frame being painted.

(i) Why is the paint attracted to the surface of

the frame?

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

(1)

(ii) After one coat of this paint the paint is no longer attracted to the frame. Explainwhy

this is.

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(1)

(b) A feature of electrostatic paint spraying is that the back of the metal frame is

painted. Explain why this happens.

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(1)

(c) A disadvantage of electrostatic paint spraying is that many other things like walls get

painted as well. Suggest how this can be avoided.

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(1)

(d) Name two other uses of electrostatic charges.

1 .....................................................................................................................................


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2 .....................................................................................................................................

(2)

(Total 6 marks)

3. (a) The diagram shows the electrical circuit symbol for a component called a light

dependent resistor.

(i) Which three letters are used to name this component?

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

(1)

(ii) How can you decrease the resistance of this component?

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(1)

(iii) How can you increase the resistance of this component?

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(1)


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(b) The sketch graph shows how the resistance of an electrical component changes as its

temperature changes.

What is this component called?

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

(1)

(c) The diagram shows an electrical circuit.

The resistance of the circuit can be changed.

(i) Name component X.

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

(1)

(ii) Put a cross next to the correct words to complete this statement. Only two crosses

should be used; one for resistance and one for current.

When the resistance is

□decreased

□increased


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the current is

□decreased

□increased

(1)

(Total 6 marks)

9. (a) A student rubs a polythene rod with a woollen cloth. He finds that the rod gains a

negative charge.

(i) Complete the sentences.

The rod is charged by ............................................. .

Electrons have been transferred from the ............................................. to the

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

(2)

(ii) When the student rubs a metal rod with a woollen cloth he finds that this rod does

not become charged. Complete the sentence.

This is because the metal rod is a good ............................................. .

(1)

(b) Electrostatic charges can be dangerous when aircraft are being refuelled. Completethe sentence.


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The electrostatic charges may cause a ............................................. to pass and this may

result in the mixture of fuel vapour and air ............................................. .

(2)

(Total 5 marks)

11. A student uses a hair dryer. The hair dryer’s plug contains a fuse.

The diagram shows the fuse.

(a) Explain how the fuse prevents too large a current in the hair dryer.

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(2)

(b) The hair dryer is rated at 240 V, 1500W. Calculate the current rating in amps of the

hair dryer.

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Current = ....................................A

(3)

(c) The fuse in the hair dryer blows and the student has to replace it. The following

fuses are available:

1 A 3 A 5 A 13 A

(i) Which fuse should the student choose? Put a cross in the correct box.

□1 A

□3 A

□5 A

□13 A

(1)

(ii) Explain your choice.

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

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

(1)

(d) A hair dryer heats up air. Name one other example of electrical heating used in the

home.

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(1)

(Total 8 marks)


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2. An electric body warmer is worn by a motorcyclist. The diagram shows a design for

an electric body warmer.

The dashed line shows a wire. When a 12 V battery is connected to the body warmer

there is a current in the wire.

(a) On the diagram draw wires connecting the body warmer to the battery.

(1)

(b) Place a cross in one box to show which of the following terms best describes the

circuit.

□ A Parallel

□ B Racing

□ C Series

□ D Short

(1)

(c) Explain why, in this design, the front of the body warmer would produce less heat

than the back.

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

(1)

(d) Suggest one other design fault.

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(1)

(e) Place a cross in one box to show which of the following properties of the wire needs

to be known if the current in the body warmer is to be calculated.

□ A colour

□ B density

□ C mass

□ D resistance

(1)

(f) Name two appliances which use electrical heating in the home.

1 ....................................................................................................................................

2 ....................................................................................................................................

(2)

(Total 7 marks)


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8. (a) The diagram shows a transformer. Use the terms from the box to label the

diagram.

(3)

(b) This transformer is a step-up transformer.

(i) Describe the difference between the input coil and the output coil.

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

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

(1)

(ii) State where a step-up transformer would be used in a large-scale electricity

transmission system.

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

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Core input coil output coil power supply


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(1)

(Total 5 marks)

9. The circuit diagram shows how a student connects several components. These

include four identical 1.5 volt cells.

(a) Identify component X.

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

(1)

(b) State a difference between a fixed resistor and a variable resistor.

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

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

(1)

(c) (i) Complete the sentence.


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The four 1.5 volt cells are called a ........................................................................

(1)

(ii) Calculate the voltage, in volts, across the four cells.

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

Voltage = ............................. V

(1)

(iii) The voltage across the fixed resistor is 3.8 V.

Calculate the voltage, in volts, across the rest of the circuit.

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

Voltage across the rest of the circuit = ................................. V

(1)

(d) The reading on ammeter R is 40 mA. State the reading in milliamps on each of the

other two ammeters.

ammeter P = .................... mA ammeter Q = .................... mA

(1)

(Total 6 marks)


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14. A student wraps an insulated wire around a large iron nail. She removes the

insulation from the ends of the wire. Then she connects the wire in the circuit shown.

(a) State the name of the device which the student has made.

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

(1)

(b) Explain why the student uses insulated wire.

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

(2)

(c) (i) Explain how the student can show that the device works.

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(1)

(ii) Explain how the student can use the device to show that iron is a magnetically soft

material.


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(1)

15. A balloon is rubbed with a dry cloth on a dry day. The balloon then sticks to a wall.

This is because the balloon has gained negative charge.

Complete the following sentences.

(a) As the balloon is rubbed, .............................................. are transferred from the

.............................................. to the .............................................. by

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

(3)


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(b) The surface of the wall near to the balloon has a ..............................................charge.

This is because objects with .............................................. charges attract each other.

(2)

(Total 5 marks)

3. The diagram shows a three-pin plug with the top removed. The earth wire and the

fuse are two of the safety features.

(a) (i) Most of the plug is made from plastic. Identify a part of the plug that must be

made from metal. Draw a line between it and the box labelled ‘Metal’.

(1)

(ii) Add the labels, earth wire and fuse, on the appropriate dotted lines on the

diagram.

(2)

(iii) State why some appliances do not need an earth wire.

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(1)

(iv) Explain what happens to a fuse when the current in it is too large.

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

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

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

(2)

(v) What is the purpose of the part of the plug labelled X?

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

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

(1)

(b) The top must be put back on before the plug is connected to a socket.

Suggest a reason why.

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

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

(1)

(Total 8 marks)


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8. (a) An experiment is performed using a transformer. The diagram shows the primary

voltage V P and the secondary voltage V S. Both voltages are drawn to the same scale.

(i) How can you tell that this transformer is acting as a step-up transformer?

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

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

(1)

(ii) The value of V S is 24 V a.c. What does the abbreviation a.c. stand for?

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

(1)

(b) An equation relating V P and V S is:

What does the term nP stand for?

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

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

(2)


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(c) State where a step-up transformer would be used in a large-scale electricity

transmission system.

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

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

(1)

(Total 5 marks)

10. (a) State an equation which relates voltage, current and resistance.

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

(1)

(b) There is an electric current in a copper wire.

(i) Complete the sentence.

This electric current is the rate of flow of .............................................................

(1)

(ii) The copper wire is replaced by an aluminium wire. This wire has the same thickness

and the same length but a greater resistance. What effect, if any, does this have on the

electric current?

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

(1)


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(c) The following circuit diagram shows the places where a student measures the current

in a circuit.

(i) Identify component V.

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

(1)

(ii) State the reading in amps on

ammeter Y reading = ........A

ammeter Z reading = ........A

(2)

(d) The following circuit diagram shows how a toymaker connects the lights in a toy

house.


The lights in the toy house are connected in .........................................................

(1)

(ii) Suggest one advantage of connecting the lights in this way.


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

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

(1)

(Total 8 marks)

2. A student connects a series circuit as shown.

(a) (i) The switch is closed. Name two components in the circuit, other than the lamp,

which affect the size of the current.

1 .............................................................................................................................

2 .............................................................................................................................

(2)


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(ii) The current is 0.40 A. Calculate the charge that flows during a time of 20 s.

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

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

Charge = ................................C

(2)

(b) You are asked to connect a second lamp so that each lamp can be switched on and

off independently. Show, by drawing on the circuit above, how this can be done.

(2)

(Total 6

marks)

13. A wire carries a current. The wire is perpendicular to a magnetic field. A force acts

on the wire and the wire moves.

(a) This effect is used in a d.c. motor.

(i) What does the abbreviation d.c. stand for?

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

(1)

(ii) Apart from electric motors, name one other device which uses this effect.

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

(1)


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(b) Professor J A Fleming invented a rule to describe the directions involved in this

effect. It is known as Fleming’s left-hand rule.

Complete the sentences.

The first finger points in the direction of the .................................... which is from

.................................... to .................................... .

The second finger points in the direction of the .................................... which is from

.................................... to .................................... .

The thumb points in the direction of the .................................... .

(5)

(c) State two ways in which the force acting on the wire can be increased.

1 ....................................................................................................................................

2 ....................................................................................................................................

(2)

(Total 9 marks)

2. A circuit contains a resistor R , a thermistor and a buzzer connected to a cell as

shown. The circuit can be used as a simple fire alarm.


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(a) (i) Complete the sentence.

When temperature increases, the resistance of a thermistor ........................................

(1)

(ii) What happens to the current in the circuit when the temperature increases?

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

(1)

(b) (i) State the equation which relates voltage, current and resistance.

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

(1)

(ii) When temperature increases, does the voltage across R stay the same, increase or

decrease?

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

(1)

(iii) Explain your answer.

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

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

(2)

(c) The buzzer starts to sound when the voltage across R is a particular value. Add a

voltmeter to the circuit diagram to show how this voltage is measured.

(1)

(Total 7 marks)


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9. The diagram shows an electrical circuit.

(a) Complete the sentence.

The .................................... across the lamp is the energy transferred per unit

.................................... passing through the lamp.

(2)

(b) Complete the table to show what each abbreviation represents in the equation

Q = I × t

One has been done for you.

Abbreviation Represents

Q

I

t time

(2)

(Total 4 marks)


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13. The diagram shows a 9 V battery.

(a) The battery contains six cells connected in series. Calculate the voltage of each cell.

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

Voltage = .............................. V

(1)

(b) Complete the sentence.

Current is the rate of flow of ........................................................................................

(1)

(c) The battery supplies an average current of 0.20 A for 3.0 hours. Use the equation

energy transferred = current × voltage × time

to calculate how much energy the battery transfers during this time and give its unit.

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

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

Energy = ..................................

(3)

(d) Describe the nature of an electric current in a metal wire.

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

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

(2)

(e) The battery is described as a 9 V d.c. supply. State what the letters d.c. stand for.

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


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(1)

(f) State two differences between a mains supply and the supply from the battery.

1 ....................................................................................................................................

2 ....................................................................................................................................

(2)

(Total 10 marks)

3. A student connects a light dependent resistor (LDR) to a battery.

(a) The current in the LDR is 0.050 A and its resistance is 90 Ω in the dark.

(i) State the equation which relates current, resistance and voltage.

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

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

(1)

(ii) Calculate the voltage across the LDR. Show your working and give the unit.

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

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

Voltage = ..................................................


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(2)

(b) The LDR is moved to a position in the light. Choose words from the box to

complete the table. You may use each word once, more than once or not at all.

Decrease increase stay the same

Effect on … It will …

the resistance of the

LDR

the current in the

LDR

(2)

(Total 5 marks)

4. (a) The diagram shows how a student connects several components in a circuit. The

student uses four identical 1.5 volt cells.

(i) Identify component Y.

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

(1)


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(ii) The reading on ammeter Z is 50 mA. What is the reading in milliamps on each of

the other two ammeters?

ammeter W = ......................... mA ammeter X = ......................... mA

(1)

(iii) The student expected the lamp to be brighter and the reading on the voltmeter to be

6.0 V. The voltmeter is working correctly.

Give two reasons why the reading on the voltmeter is less than 6.0 V.

1 .............................................................................................................................

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

(1)

2 .............................................................................................................................

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

(1)

(b) The graph shows how the current in a filament lamp varies with the voltage across

it.

Explain why the graph is not a straight line.

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

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

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


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

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

(3)

(Total 7 marks)

6. (a) When you rub a polythene rod with a woollen cloth the rod becomes negatively

charged.

(i) Complete the labels on the diagram.

(1)

(ii) Explain why

the polythene rod then remains negatively charged for some time.

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

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

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

(2)

(iii) If you rub a copper rod rather than a polythene rod, the copper rod will not stay

charged. Why not?

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

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

(1)

(b) Complete the following.


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When a petrol tanker is filled or emptied the build-up of charge can be dangerous. This

is because a ........................................ may occur and this can ignite the petrol vapour

and cause an explosion.

(1)

(Total 5 marks)

8. (a) Complete the sentence.

Voltage is ............................................................ across a copper coil when a

............................................................ changes through the coil.

(2)

(b) A transformer is used to change the size of an alternating voltage. Complete theequation for a transformer.

(1)

(c) Transformers are used in the large-scale transmission of electrical energy. Choose

phrases from the box to complete the sentences. You may use each phrase once, more

than once or not at all.

in the pylons

in the transmission line

in the turbine

just after the transmission line

just before the generator

just before the transmission line

(i) In the transmission system a step-up transformer must be located

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


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(1)

(ii) In the transmission system a step-down transformer must be located

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

(1)

(Total 5 marks)

16. (a) Complete the sentence:

Voltage is the .............................. transferred per unit .............................. passed.

(1)

(b) The circuit diagram shows a 1.5 V cell connected to a resistor. The current in the

circuit is 0.60 A.

(i) How much charge in coulombs

flows through the cell in 2.0 s?

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

Charge flowing = ................................................. C

(2)

(ii) How much energy in joules is transferred to the resistor during this time?

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

Energy transferred = ............................................... J

(2)

(iii) State one assumption you have made in (ii).

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

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

(1)


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(c) State two changes to the value of the circuit components that would each allow four

times as much energy to be transferred to a resistor in a two-second period.

1 ....................................................................................................................................

2 ....................................................................................................................................

(2)

(Total 8 marks)

11. The circuit diagram shows a metal filament lamp connected in series to a battery, a

closed switch and a component X.

(a) What is component X?

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

(1)

(b) Adjusting component X alters the current in the lamp.

Complete the sentence.

Current is the ........................................... of flow of ............................................

(1)

(c) Complete the table for the equation in the box by writing the unit name in full.

Q = I × t


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Abbreviation for

quantity

Unit for

quantity

Q

I

t

(3)

(d) (i) Name the particles which flow in the wire from A to B.

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

(1)

(ii) Explain why they flow in this direction.

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

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

(1)

(Total 7 marks)

13. A laptop computer has a rechargeable battery. The battery takes 4 hours to charge

fully when a voltage of 6 V is used with a current of 1.2 A.

(a) Use the equation

energy transferred = current × voltage × time


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to calculate the energy transferred. Show your working and give the unit.

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

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

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

Energy = ..................................................

(3)

(b) Complete the sentences.

(i) Voltage is the energy transferred per unit ................................................ passed.

(1)

(ii) A volt is a joule per ................................................ .

(1)

(Total 5 marks)

1. The circuit diagram shows how a student connects several components. These

include four identical 1.5 volt cells.

(a) Identify component X.

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

(1)

(b) State a difference between a fixed resistor and a variable resistor.

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

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

(1)


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(c) (i) Complete the sentence.

The four 1.5 volt cells are called a ........................................................................

(1)

(ii) Calculate the voltage, in volts, across the four cells.

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

Voltage = ............................. V

(1)

(iii) The voltage across the fixed resistor is 3.8 V. Calculate the voltage, in volts, across

the rest of the circuit.

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

Voltage across the rest of the circuit = ................................. V

(1)

(d) The reading on ammeter R is 40 mA. State the reading in milliamps on each of the

other two ammeters.

ammeter P = .................... mA ammeter Q = .................... mA

(1)

(Total 6 marks)


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9. (a) Put a cross in two boxes to show which of the following statements are correct.

□ A 1 V is the ratio of energy transferred to charge passed.

□ B 1 V is the voltage when a current of 1 A dissipates 1 W of power.

□ C 1 V is the voltage when 1 J of energy is transferred when 1 C of charge passes.

□ D 1 V is the ratio of resistance to current.

(2)

(b) The diagram shows a battery connected to a resistor.

The terms ‘conventional flow’ and ‘electron flow’ are both used in current electricity.

(i) Which one is represented by the arrow in this circuit?

.......................................... flow

(1)

(ii) Explain your answer in (i).

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

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

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

(1)


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(iii) A student set up this circuit. She added an ammeter to measure the current in the

circuit and a voltmeter to measure the voltage across the resistor. Add these meters to

the circuit diagram.

(2)

(c) The student also had a stopwatch. She recorded the following readings:

V = 3.0 V

I = 0.75 A

t = 2.0 minutes.

Calculate:

(i) the charge, in coulombs, passing through the resistor in 2.0 minutes

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

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

Charge = .............................. C.

(2)

(ii) the energy, in joules, transferred to the resistor in 2.0 minutes.

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

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

Energy transferred = ................................. J

(2)

(Total 10 marks)

1. (a) State an equation which relates voltage,

current and resistance.

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


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(1)

(b) There is an electric current in a copper wire.


This electric current is the rate of flow of .............................................................

(1)

(ii) The copper wire is replaced by an aluminium wire. This wire has the same thickness

and the same length but a greater resistance. What effect, if any, does this have on the

electric current?

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

(1)

(c) The following circuit diagram shows the places where a student measures the current

in a circuit.

(i) Identify component V.

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

(1)

(ii) State the reading in amps on

ammeter Y reading = .........A

ammeter Z reading = .........A


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(2)

(d) The following circuit diagram shows how a toymaker connects the lights in a toy

house.


The lights in the toy house are connected in .........................................................

(1)

(ii) Suggest one advantage of connecting the lights in this way.

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

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

(1)

(Total 8 marks)

3. The circuit symbol for a fuse is


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A student reads the following in an article. Some 1 A fuses can take 10 A for 0.1 s to

allow for a large current when a circuit is first switched on.

He decides to investigate this statement by allowing different values of current above 1

A in a 1 A fuse and measuring how long it takes to blow.

His experiment produced results shown by the graph.

(a) Describe how the student would perform this experiment. Your description shouldinclude:

• a circuit diagram

• values for the circuit components

• the range of the meter

• method used.

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

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

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

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

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

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


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

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

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

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

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

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

(9)

(b) During the student’s investigation he took readings from an ammeter and a

stopwatch. Record his readings.

............................ A................................ s

(2)

(Total 11 marks)


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4. Metal rods with currents in the same direction attract as shown.

(a) Two metal rods are to be connected in series to a d.c. power supply, an ammeter and

a variable resistor.

(i) Complete the diagram of the circuit. The power supply, one connecting wire and the

two metal rods are already shown.

(4)

(ii) Add arrows to show the direction of the current in all parts of the circuit.

(2)

(iii) Explain whether the metal rods in your circuit will attract.

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

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

(1)


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(b) In another experiment one of the metal rods is suspended from two identical metal

springs. The other metal rod is fixed vertically below the suspended metal rod. The rods

are both horizontal. The rods and the springs are connected into a circuit.

Diagram 1 shows the separation of the rods when there is a current of 1 A in the springs

and the rods.

Diagram 1

Diagram 2 shows the separation of the rods when the current is adjusted to 2 A.

Diagram 2

Diagram 3 shows the ammeter after another adjustment to the current.

Diagram 3

(i) Measure the separation in mm of the rods with the current of 2 A.

Separation = ..................... mm

(1)


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(ii) Read the value of current, in A.

Current = ......................... A

(1)

(iii) Suggest a value for the separation of the rods for the current shown in Diagram 3.

Separation = ..................... mm

(1)

(iv) The circuit is removed and there is no current in the rods. You can now use the

apparatus to see if Hooke’s law is obeyed for two identical metal springs in parallel.

You are provided with some small unknown masses to extend the springs.

Where would you place the masses? Explain your answer.

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

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

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

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

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

(3)

(Total 13 marks)

3. A student designed a small electric heater. The diagram shows how he used his

heater.


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(a) Suggest the purpose of the polystyrene pellets.

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

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

(1)

(b) The student measured the temperature of the water in the small beaker using a

thermometer.

What should be done to the water before measuring its temperature?

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

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

(1)

(c) The student then closed the switch and noted the readings on meters X and Y.

(i) Each diagram shows a meter.

What is the numerical reading on each meter?


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Reading = .............................. Reading = ..............................

(1)

(ii) Name meter X.

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

(1)

(iii) Name meter Y.

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

(1)

(iv) After 5 minutes he opened the switch and measured the new temperature of the

water.

The diagrams show two thermometers. What is the reading on each thermometer and

what is the difference between the readings?

Reading = .............. °C Reading = .............. °C Difference = .............. °C

(2)

(d) The student repeated the experiment several times. Each time he used an identical

mass of water at the same starting temperature. He adjusted the variable resistor to give

different values of current and voltage before heating the water for five minutes.

He expected to find that the temperature increase is proportional to the power.

Suggest and explain two experimental reasons why this did not happen.


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1 ....................................................................................................................................

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

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

(2)

2 ....................................................................................................................................

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

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

(2)

(Total 12 marks)


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4. The diagram shows a rheostat (variable resistor) together with its circuit symbol.


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The slider can be moved. When the distance L is changed, the resistance of the rheostat

is changed. The maximum value of L is 19 cm.

A student investigates how the current I in the rheostat depends on the length L.

(a) In the space below draw a circuit diagram for this investigation.

(2)

(b) (i) State one extra item of equipment, not shown on your diagram, that the student

would need.

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

(1)

(ii) Describe how this investigation would be carried out.

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

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

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

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

(3)


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(c) During the investigation, the ammeter reading was as shown below.

Record this reading.

Current = ................................... A

(1)

(d) During the investigation the student recorded the following results.

19, 0.11 10, 0.17 7, 0.24

5, 0.33 6, 0.14 16, 0.12

(i) Put these results in a table with column headings and units.


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(3)

(ii) Using the grid plot a graph of current against length. Label the axes.

(3)

(iii) Circle the anomalous (unexpected) result.

(1)

(iv) Draw the best-fit curve for the remaining points.

(1)

(v) Suggest a reason for the anomalous result.

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

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

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

(1)


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(e) Suggest wh

Igcse e Electricity With Msc

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