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2.1 Electricity – Low Demand – Questions

Q1.Figure 1 shows the circuit symbol for three different components.

Figure 1

(a) Which component is a variable resistor?

Tick one box.

A B C

(1)

(b) Which component is a thermistor?

Tick one box.

A B C

(1)

(c) In which component will the resistance decrease when the temperature increases?

Tick one box.

A B C

(1)

(d) In which component will the resistance decrease when the light intensity increases?

Tick one box.

A B C

(1)

Figure 2 shows four different arrangements of resistors.

Figure 2

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(e) Two of the arrangements are in series and two are in parallel.

Describe the difference between a series and a parallel arrangement.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(f) Which arrangement has a resistance of 10 Ω?

Tick one box.

P Q R S

(1)

(g) Which arrangement has the highest resistance?

Tick one box.

P Q R S

(1)

(h) A student connects a resistor to a cell for 60 seconds.

The current through the resistor is 0.97 A

Calculate the charge flow.

Use the equation:

charge flow = current × time

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Give your answer to 2 significant figures.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Charge flow = ____________________ C(3)

(Total 11 marks)

Q2.(a) Electrical circuits often contain resistors.

The diagram shows two resistors joined in series.

Calculate the total resistance of the two resistors.

___________________________________________________________________

Total resistance = _________________________ Ω(1)

(b) A circuit was set up as shown in the diagram. The three resistors are identical.

(i) Calculate the reading on the voltmeter.

______________________________________________________________

______________________________________________________________

Reading on voltmeter = _________________________ V(2)

(ii) The same circuit has now been set up with two ammeters.

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Draw a ring around the correct answer in the box to complete the sentence.

smaller than

The reading on ammeter A2 will be equal to the reading on ammeter A1.

greater than

(1)(Total 4 marks)

Q3.Figure 1 shows a three pin plug connected to the cable of a metal toaster.

Figure 1

(a) Name wire X.

___________________________________________________________________(1)

(b) What does wire X do?

Tick one box.

It provides extra energy to the toaster when needed.

It completes the circuit in the toaster.

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It can prevent an electric shock from the toaster.

It supplies the current to the toaster.

(1)

(c) The toaster is plugged in to the mains electricity supply.

What is the potential difference between the live and neutral wires?

Tick one box.

0 V 120 V 230 V 460 V

(1)

(d) Mains electricity is an alternating supply.

A battery is a direct supply.

Figure 2 shows an alternating supply and a direct supply.

Figure 2

Give two differences between the alternating supply and the direct supply.

1. _________________________________________________________________

2. _________________________________________________________________(2)

Energy is transferred to homes by the National Grid.

Figure 3 shows the percentage energy losses over the National Grid for different years.

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Figure 3

(e) Describe the changes in percentage energy loss.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(f) Calculate the mean percentage energy loss per year in Figure 3.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Mean energy loss per year = ____________________ %(3)

(Total 10 marks)

Q4.Figure 1 shows the information label from a hairdryer.

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Figure 1

(a) What is the power of the hairdryer?

Tick one box.

50 Hz

230 V

2100 W

(1)

(b) What is the equation which links current, potential difference and power?

Tick one box.

power = potential difference × current

(1)

(c) The mains electricity supply in the UK is an alternating current (ac).

What is the frequency of the UK ac supply?

___________________________________________________________________(1)

(d) Some electrical appliances use batteries.

What type of current does a battery supply?

Tick one box.

Alternating current (ac) only

Direct current (dc) only

Both ac and dc

Not ac or dc

(1)

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The hairdryer is connected to the mains electricity supply by a plug.

Figure 2 shows the inside of a plug.

Figure 2

(e) Draw one line from each wire to the colour of insulation around the wire.

Wire Colour of insulation around wire

Blue

Live Brown

Green

Neutral White

Yellow

(2)

(f) The insulation around the Earth wire has two colours.

What are the two colours?

____________________ and ____________________(1)

(g) Brass is an alloy of copper and zinc.

Give two properties of brass that make it suitable to use in the plug.

1. _________________________________________________________________

2. _________________________________________________________________(2)

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(h) Figure 3 shows how the National Grid links power stations to consumers.

Figure 3

Describe how electrical power is transferred from power stations to consumers by the National Grid.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(4)

(Total 13 marks)

Q5.Components can be connected in electrical circuits in different ways.

(a) Draw one line from each circuit symbol to the name of the component it represents.

Circuit symbol Name of component

cell

diode

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fuse

lamp

variable resistor

(2)

(b) Complete the sentence.

Choose the answer from the box.

charge energy potential difference resistance

Electric current is the rate of flow of ____________________.(1)

Figure 1 shows a parallel circuit.

Figure 1

(c) Calculate the current measured by ammeter A2.

Current = ____________________ A(1)

(d) The circuit is connected for 300 s

The total current in the circuit stays at 0.56 A

Calculate the total charge flow.

Use the equation:

charge flow = current × time

___________________________________________________________________

___________________________________________________________________

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___________________________________________________________________

___________________________________________________________________

Charge flow = ____________________ C(2)

(e) The potential difference supplied by the battery is 4.5 V

Calculate the total energy transferred in 300 s

Use the equation:

energy transferred = charge flow × potential difference

Use your answer to part (d).

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Energy transferred = ____________________ J(2)

(f) Figure 2 shows a series circuit.

Figure 2

Resistor R2 breaks.

What happens to the reading on the ammeter?

___________________________________________________________________(1)

(g) Figure 3 shows a parallel circuit.

Figure 3

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Resistor R3 breaks.

What happens to the readings on the ammeter?

Ammeter A1 _________________________________________________________

Ammeter A2 _________________________________________________________(2)

Figure 4 shows how the resistance of a component varies with temperature.

Figure 4

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(h) What is the name of the component?

Tick one box.

LED

LDR

Resistor

Thermistor

(1)

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(i) What is the resistance of the component at a temperature of 50 °C?

Resistance = ____________________ Ω(1)

(Total 13 marks)

Q6.Most electrical appliances are connected to the mains electricity using three-core cables.

(a) What is the approximate value of the potential difference of the UK mains electricity supply?

Tick one box.

23 V

230 V

300 V

350 V

(1)

(b) Figure 1 shows a three-core cable.

Figure 1

Use answers from the box to label the wires and complete Figure 1.

Earth Negative Neutral

(2)

(c) In the UK the three wires in a three-core cable are always the same colours.

Why are the wires always the same colours?

Tick one box.

Each wire is made by a different company.

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It is easy to identify each wire.

They are cheaper to manufacture.

(1)

(d) Touching the live wire is dangerous.

Use answers from the box to complete the sentences.

current resistance shock force voltage

Touching the live wire causes a large potential difference to exist across the body.

This causes a _____________________________ through the body, which

results in an electric _____________________________(2)

(e) What is the approximate frequency of the UK mains electricity supply?

Tick one answer.

50 Hz

75 Hz

100 Hz

150 Hz

(1)

(f) Figure 2 shows how power stations transfer electrical power to consumers using the National Grid.

Figure 2

The power station generates electricity at a voltage of 25 kV.

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Transformer A increases the voltage by a factor of 16.

What is the voltage output of transformer A?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Output voltage = _____________________ kV(2)

(g) Why is the voltage increased by transformer A?

Tick one box.

To reduce the energy lost due to heating

To increase the power

To increase the current

(1)

(h) Why is it important that the voltage is decreased by transformer B?

Tick one box.

Less energy is used by consumers

It is safer for consumers

It reduces consumers’ electricity bills

(1)(Total 11 marks)

Q7.(a) Figure 1 shows the oscilloscope trace an alternating current (a.c.) electricity supply

produces.

Figure 1

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One vertical division on the oscilloscope screen represents 5 volts.

Calculate the peak potential difference of the electricity supply.

___________________________________________________________________

Peak potential difference = _________________________ V(1)

(b) Use the correct answer from the box to complete the sentence.

40 50 60

In the UK, the frequency of the a.c. mains electricity supply is ______ hertz.(1)

(c) Figure 2 shows how two lamps may be connected in series or in parallel to the 230 volt mains electricity supply.

Figure 2

(i) Calculate the potential difference across each lamp when the lamps are connected in series.

The lamps are identical.

______________________________________________________________

Potential difference when in series = ___________ V(1)

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(ii) What is the potential difference across each lamp when the lamps are connected in parallel?

Tick () one box.

115 V 230 V 460 V

(1)

(iii) Give one advantage of connecting the lamps in parallel instead of in series.

______________________________________________________________

______________________________________________________________(1)

(d) Figure 3 shows the light fitting used to connect a filament light bulb to the mains electricity supply.

Figure 3

The light fitting does not have an earth wire connected.

Explain why the light fitting is safe to use.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(e) A fuse can be used to protect an electrical circuit.

Name a different device that can also be used to protect an electrical circuit.

___________________________________________________________________(1)

(Total 8 marks)

Q8.

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Figure 1 shows the apparatus used to investigate how the current through a thermistor depends on the temperature of the thermistor.

Figure 1

(a) Which one of the following is the correct circuit symbol for a thermistor?

Tick () one box.

(1)

(b) To get a range of results, hot water at 60 °C was poured into the beaker.The temperature of the water and current through the thermistor were then recorded as the water cooled.

The results of the investigation are shown in Figure 2.

Figure 2

(i) Suggest one way the investigation could have been changed to give a wider range of temperatures.

______________________________________________________________

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______________________________________________________________(1)

(ii) Describe how the current through the thermistor depends on the temperature of the thermistor.

______________________________________________________________

______________________________________________________________(1)

(iii) Use Figure 2 to determine the current through the thermistor at 40 °C.

Current at 40 °C = ___________ A(1)

(iv) At 40 °C the thermistor has a resistance of 250 Ω.

Use your answer to part (iii) and the resistance of the thermistor to calculate the potential difference across the thermistor.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

Potential difference = ___________ V(2)

(v) The potential difference across the thermistor stays the same all through the investigation.

What conclusion can be made from the results in Figure 2 about the resistance of the thermistor as the temperature of the thermistor decreases?

Tick () one box.

the resistance increases

the resistance does not change

the resistance decreases

(1)(Total 7 marks)

Q9.Many electrical appliances are connected to the mains supply using a three-core cable and a three-pin plug.

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(a) Use the correct answer from the box to complete the sentence.

charge energy power

Electric current is the rate of flow of _______________________________ .(1)

(b) The diagram shows a three-pin plug connected to a three-core cable.

(i) The three wires of the three-core cable have different coloured coverings.

State the colour of the covering of the neutral wire.

______________________________________________________________(1)

(ii) Which two parts of the plug shown above protect the wiring of a circuit?

Tick ( ) two boxes.

Tick ( )

Earth wire

Fuse

Live wire

Neutral wire

(2)

(c) Some electrical appliances are connected to the mains supply using a two-core cable and a three-pin plug. Appliances that are double insulated do not require all three wires.

(i) What does ‘double insulated’ mean?

______________________________________________________________

______________________________________________________________(1)

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(ii) State which of the three wires is not required.

______________________________________________________________(1)

(d) (i) An electrical appliance is connected to a 20 V supply.

The current in the appliance is 3 A.

Calculate the power of the appliance.

______________________________________________________________

______________________________________________________________

Power = _________________________ W(2)

(ii) Another electrical appliance is connected to a 20 V supply.

The appliance transfers 300 J of energy.

Calculate the charge.

Give the unit.

______________________________________________________________

______________________________________________________________

Charge = _________________________

Unit _____________(3)

(Total 11 marks)

Q10.The graph shows how the current through a filament bulb changes after the bulb is switched on.

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(a) What happens to the current through the bulb in the first 0.02 seconds after the bulb is switched on?

___________________________________________________________________(1)

(b) Between 0.02 seconds and 0.08 seconds the current through the bulb decreases.

(i) What, if anything, happens to the resistance of the bulb between 0.02 seconds and 0.08 seconds?

Draw a ring around the correct answer.

decreases does not change increases

(1)

(ii) What, if anything, happens to the temperature of the bulb between 0.02 seconds and 0.08 seconds?


decreases does not change increases

(1)

(c) The bulb is connected to a 12 V power supply.

Calculate the power of the bulb when the current through the bulb is 1.5 A.

Choose the unit from the list below.

coulomb joule watt

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___________________________________________________________________

___________________________________________________________________

Power = ____________________ unit ________________(3)

(Total 6 marks)

Q11.(a) A resistor is a component that is used in an electric circuit.

(i) Describe how a student would use the circuit to take the readings necessary to determine the resistance of resistor R.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________(6)

(ii) Explain why the student should open the switch after each reading.

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______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________(2)

(iii) In an experiment using this circuit, an ammeter reading was 0.75 A.The calculated value of the resistance of resistor R was 16 Ω.

What is the voltmeter reading?

______________________________________________________________

______________________________________________________________

Voltmeter reading = ________________ V(2)

(iv) The student told his teacher that the resistance of resistor R was 16 Ω.

The teacher explained that the resistors used could only have one of the following values of resistance.

10 Ω 12 Ω 15 Ω 18 Ω 22 Ω

Suggest which of these resistors the student had used in his experiment.

Give a reason for your answer.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________(2)

(b) The diagram shows a fuse.

Describe the action of the fuse in a circuit.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

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___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(3)

(Total 15 marks)

Q12.(a) Draw one line from each circuit symbol to its correct name.

Circuit symbol Name

Diode

Light-dependentresistor (LDR)

Lamp

Light-emittingdiode (LED)

(3)

(b) Figure 1 shows three circuits.

The resistors in the circuits are identical.

Each of the cells has a potential difference of 1.5 volts.

Figure 1

Circuit 1 Circuit 2 Circuit 3

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(i) Use the correct answer from the box to complete the sentence.

half twice the same as

The resistance of circuit 1 is _________________ the resistance of circuit 3.(1)

(ii) Calculate the reading on voltmeter V2.

______________________________________________________________

Voltmeter reading V2 = _______________ V(1)

(iii) Which voltmeter, V1, V2 or V3, will give the lowest reading?


V1 V2 V3

(1)

(c) A student wanted to find out how the number of resistors affects the current in a series circuit.

Figure 2 shows the circuit used by the student.

Figure 2

The student started with one resistor and then added more identical resistors to the circuit.

Each time a resistor was added, the student closed the switch and took the ammeter reading.

The student used a total of 4 resistors.

Figure 3 shows three of the results obtained by the student.

Figure 3

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Number of resistors in series

(i) To get valid results, the student kept one variable the same throughout the experiment.

Which variable did the student keep the same?

______________________________________________________________(1)

(ii) The bar chart in Figure 3 is not complete. The result using 4 resistors is not shown.

Complete the bar chart to show the current in the circuit when 4 resistors were used.

(2)

(iii) What conclusion should the student make from the bar chart?

______________________________________________________________

______________________________________________________________(1)

(Total 10 marks)

Q13.(a) A student used the apparatus drawn below to investigate the heating effect of an

electric heater.

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(i) Before starting the experiment, the student drew Graph A.

Graph A shows how the student expected the temperature of the metal block to change after the heater was switched on.

Describe the pattern shown in Graph A.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________(2)

(ii) The student measured the room temperature. He then switched the heater on and measured the temperature of the metal block every 50 seconds.

The student calculated the increase in temperature of the metal block and plotted Graph B.

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After 300 seconds, Graph B shows the increase in temperature of the metal block is lower than the increase in temperature expected from Graph A.

Suggest one reason why.

______________________________________________________________

______________________________________________________________(1)

(iii) The power of the electric heater is 50 watts.

Calculate the energy transferred to the heater from the electricity supply in 300 seconds.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Energy transferred = ______________________ J(2)

(b) The student uses the same heater to heat blocks of different metals. Each time the heater is switched on for 300 seconds.

Each block of metal has the same mass but a different specific heat capacity.

Metal Specific heat capacity in J/kg°C

Aluminium 900

Iron 450

Lead 130

Which one of the metals will heat up the most?


aluminium iron lead

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Give, in terms of the amount of energy needed to heat the metal blocks, a reason for your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(Total 7 marks)

Q14.(a) The diagram shows the information plate on an electric kettle. The kettle is plugged

into the a.c. mains electricity supply.

230 V 2760 W

50 Hz

Use the information from the plate to answer the following questions.

(i) What is the frequency of the a.c. mains electricity supply?

______________________________________________________________(1)

(ii) What is the power of the electric kettle?

______________________________________________________________(1)

(b) To boil the water in the kettle, 2400 coulombs of charge pass through the heating element in 200 seconds.

Calculate the current flowing through the heating element and give the unit.

Choose the unit from the list below.

amps volts watts

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Current = ______________________________(3)

(c) The amount of charge passing through the heating element of an electric kettle depends on the time the kettle is switched on.

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What pattern links the amount of charge passing through the heating element and the time the kettle is switched on?

___________________________________________________________________

___________________________________________________________________(2)

(Total 7 marks)

Q15.(a) The diagram shows the traces produced on an oscilloscope when it is connected

across different electricity supplies.

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Which of the traces could have been produced by the mains electricity supply?

___________________________________________________________________


___________________________________________________________________

___________________________________________________________________(2)

(b) The picture shows two adaptors being used to plug five electrical appliances into the same socket.

Explain why it is dangerous to have all five appliances switched on and working at the same time.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(Total 4 marks)

Q16.(a) The diagram shows a simple circuit.

(i) Calculate the total resistance of the two resistors in the circuit.

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______________________________________________________________


(ii) Calculate the reading on the voltmeter.

Show clearly how you work out your answer.

______________________________________________________________

______________________________________________________________

Voltmeter reading = _________________________ V(2)

(iii) Draw a ring around the correct answer in the box to complete the sentence.

Replacing one of the resistors with a resistor of higher value will

decrease

not change

increase

the reading on the ammeter.(1)

(b) The voltmeter in the circuit is replaced with an oscilloscope.

Which one of the diagrams, X, Y or Z, shows the trace that would be seen on the oscilloscope?

Write your answer, X, Y or Z, in the box.

Diagram


___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

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(Total 6 marks)

Q17.A student used the apparatus below to find out how the resistance of a light-dependent resistor (LDR) depends on light intensity.

The resistance of the LDR was measured directly using a multimeter.

(a) (i) Which one of the following is the correct circuit symbol for a LDR?

Draw a ring around your answer.

(1)

(ii) Name one factor that will affect the intensity of the light hitting the LDR.

______________________________________________________________

______________________________________________________________(1)

(b) The manufacturer of the LDR provides data for the LDR in the form of a graph.

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Describe how the resistance of the LDR changes when the light intensity increases from 100 lux to 300 lux.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(c) The student only obtained three results. These are given in the table.

Light intensity Resistance in kilohms

Dark 750

Bright 100

Very bright 1

(i) The student could not use the results to draw a line graph.Why not?

______________________________________________________________

______________________________________________________________(1)

(ii) Do the student’s results agree with the data the manufacturer provided?

Draw a ring around your answer. YES NO


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______________________________________________________________

______________________________________________________________

______________________________________________________________(1)

(d) Which one of the following circuits probably includes a LDR?

Tick ( ) one box.

A circuit that automatically switches outside lights on when it gets dark.

A circuit that automatically switches central heating on and off.

A circuit that automatically turns lights off when no one is in the room.

(1)(Total 7 marks)

Q18.Each letter, A, B, C, D and E, represents an energy transformation.

A electrical to chemicalB electrical to heatC electrical to kineticD electrical to lightE electrical to sound

Match each of the following devices to the useful energy transformation that the device is designed to make.

Write the correct letter, A, B, C, D or E, in the box below each device.

Use each letter no more than once.

Fan Kettle Lamp Radio

(Total 4 marks)

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Q19.(a) The diagram shows the circuit that a student used to investigate how the current

through a resistor depends on the potential difference across the resistor.

(i) Each cell provides a potential difference of 1.5 volts.

What is the total potential difference provided by the four cells in the circuit?

______________________________________________________________

Total potential difference = _________________________ volts(1)

(ii) The student uses the component labelled X to change the potential difference across the resistor.

What is component X?


light-dependent resistor thermistor variable resistor

(1)

(iii) Name a component connected in parallel with the resistor.

______________________________________________________________(1)

(b) The results obtained by the student have been plotted on a graph.

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(i) One of the results is anomalous.

Draw a ring around the anomalous result.(1)

(ii) Which one of the following is the most likely cause of the anomalous result?

Put a tick ( ) in the box next to your answer.

The student misread the ammeter.

The resistance of the resistor changed.

The voltmeter had a zero error.

(1)

(iii) What was the interval between the potential difference values obtained by the student?

______________________________________________________________

______________________________________________________________(1)

(c) Describe the relationship between the potential difference across the resistor and the current through the resistor.

___________________________________________________________________

___________________________________________________________________(1)

(Total 7 marks)

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Q20.(a) The lamps in the circuits drawn below are all identical.

Each of the cells has a potential difference of 1.5 volts.

(i) What is the potential difference across the 3 cells that are joined in series?

______________________________________________________________

Potential difference = _________________________ V(1)

(ii) What will be the reading on the voltmeter labelled V3?

Voltmeter reading V3 = _________________________ V(1)

(iii) Which voltmeter, V1, V2 or V3, will give the highest reading?


V1 V2 V3

(1)

(b) The diagram below shows a simple circuit.

(i) Calculate the total resistance of the two resistors in the circuit.

______________________________________________________________


(ii) Use the equation in the box to calculate the reading on the voltmeter.

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potential difference = current × resistance


______________________________________________________________

______________________________________________________________

Voltmeter reading = _________________________ V(2)

(iii) The current through a resistor at constant temperature changes when the potential difference across the resistor changes.

Which one of the graphs, X, Y or Z, shows how the current changes?

Write your answer, X, Y or Z, in the box.

X

Y

Z

Graph (1)

(Total 7 marks)

Q21.The diagram shows an electric circuit used in a dolls’ house.The switches are 2-way switches; this means that each switch has a connecting wire that can be in one of two positions.

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(a) (i) With the connecting wire in each switch in the position shown in the diagram, the lamp is off. Why?

______________________________________________________________

______________________________________________________________(1)

(ii) When switched on, the lamp has a resistance of 18 Ω and draws a current of 0.5 A from the power supply.

Use the equation in the box to calculate the potential difference of the power supply used in the circuit.



______________________________________________________________

______________________________________________________________

Potential difference = _________________________ V(2)

(iii) A second, identical lamp is added to the circuit. The two lamps are joined in series.

Calculate the total resistance of the two lamps.

______________________________________________________________


(b) This type of circuit is also used in real houses. One of the switches is at the top of the stairs, and the other switch is at the bottom of the stairs.

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What is the advantage of using this circuit to switch a lamp on or off, rather than using a more simple circuit that has only one switch?

___________________________________________________________________

___________________________________________________________________(1)

(c) The diagram shows an old type of metal lamp fitting.

The cable has been connected to the lamp fitting in a way that makes the lamp fitting unsafe.

(i) What is the possible risk to someone touching the lamp fitting while the lamp is switched on?

______________________________________________________________

______________________________________________________________(1)

(ii) What should be done to make this lamp fitting safe to use?

______________________________________________________________

______________________________________________________________(1)

(Total 7 marks)

Q22.A circuit diagram is shown below.

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(a) Use a word from the box to label component X.

fuse switch thermistor

(1)

(b) Calculate the total resistance of the two resistors in the circuit.

___________________________________________________________________

Total resistance = ____________________ Ω(1)

(c) The reading on the ammeter is 0.25 A.

The current through the 6 Ω resistor will be:

bigger than 0.25 A equal to 0.25 A smaller than 0.25 A

Draw a ring around your answer(1)

(d) The 6 V battery is made by correctly joining several 1.5 V cells in series.

Calculate the number of cells needed to make the battery.

___________________________________________________________________

Number of cells = ______________________(1)

(Total 4 marks)

Q23.The diagram shows a simple circuit.

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(a) The circuit includes an LDR.

What do the letters LDR stand for?


Light-dependable resistor light-dependent resistor light-direct resistor

(1)

(b) The graph shows how the resistance of an LDR changes with light intensity.

Describe in detail how the resistance of the LDR changes as the light intensity increases from 0 to 50 lux.

___________________________________________________________________

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___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(3)

(c) (i) Complete the following sentence by drawing a ring around the correct line in the box.

decrease

A decrease in the light intensity of light on the LDR will not change the

increase

reading on the ammeter.(1)

(ii) Give a reason for your answer to part (c)(i).

______________________________________________________________

______________________________________________________________(1)

(d) An LDR can be used to switch a circuit on and off automatically.

In which one of the following would an LDR be used?


a circuit to switch on central heating when it gets cold

a circuit to switch on security lighting when it gets dark

a circuit to switch on a water sprinkler when the soil in a greenhouse is dry

(1)(Total 7 marks)

Q24.(a) The diagram shows two switches on a room heater. The heater has three power

settings. The power produced by two of the settings is given in the table.

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Setting Power in kW

Low 0.5

Medium 1.5

High

(i) When both switches are on, the heater works at the high power setting.

What is the power of the heater when it is switched to the high power setting?

______________________________________________________________

Power = _____________________________ kW(1)

(ii) The heater is used on the medium power setting. It is switched on for three hours.

Use the equation in the box to work out the energy transferred from the mains to the heater in three hours.

energy transferred(kilowatt-hour, kWh) = power

(kilowatt, kW) × time(hour, h)


______________________________________________________________

______________________________________________________________

Energy transferred = ___________________ kWh(2)

(iii) Electricity costs 12 pence per kilowatt-hour.

Use the equation in the box to calculate how much the heater costs to use on medium power for three hours.

total cost = number of kilowatt-hours × cost per kilowatt-hour


______________________________________________________________

______________________________________________________________

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Total cost = ________________________ pence(2)

(b) The heater is used to warm a room.

The graph shows how the temperature of the room changes from the moment the heater is switched on.

The heater was first used on the medium setting.

(i) At what time was the heater setting changed to the high setting?

_______________________________


______________________________________________________________

______________________________________________________________

______________________________________________________________(2)

(ii) From 7 pm until 10 pm, the temperature of the room is not changing.

Which one of the following statements gives the reason why the temperature of the room is not changing?


The room is losing energy slower than the heater supplies energy.

The room is losing energy as fast as the heater supplies energy.

The room is losing energy faster than the heater supplies energy.

(1)(Total 8 marks)

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Q25.A student used a joulemeter to measure the energy transformed by a lamp.

The student set the joulemeter to zero, and then switched on the power supply.

After 120 seconds (2 minutes), the reading on the joulemeter had increased to 2880.

(a) In the space below, draw the circuit symbol used to represent a lamp.

(1)

(b) (i) Use the equation in the box to calculate the power of the lamp.


______________________________________________________________

______________________________________________________________

Power = _________________________(2)

(ii) Which one of the following is the unit of power?


joule newton watt

(1)

(c) Complete the following sentence using one of the phrases from the box.

larger than the same as smaller than

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If the lamp was left switched on for 10 minutes, the amount of energy transformed

would be ______________________________________ the amount of energy

transformed in 2 minutes.(1)

(Total 5 marks)

Q26.(a) The diagram shows the circuit used by a student to measure the power of a filament

lamp.

Name a component connected in parallel with the filament lamp.

___________________________________________________________________(1)

(b) By adding another component to the circuit, the student is able to obtain a range of ammeter and voltmeter readings.

Ammeter reading in

amps

Voltmeter reading in

volts

0.10 1.0

0.15 2.0

0.20 4.0

0.25 7.0

0.30 11.0

(i) Which one of the following components did the student add to the circuit?


fuse switch variable resistor(1)

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(ii) What is the range of ammeter readings taken by the student?

from _______________ amps to _______________ amps(1)

(iii) Use the data in the table and the equation in the box to calculate the maximum power of the filament lamp.


______________________________________________________________

______________________________________________________________

Power = _______________ W(3)

(c) Complete the following sentence by drawing a ring around the correct line in the box.

increases

As the temperature of a filament lamp increases, its resistance remains constant

decreases

(1)(Total 7 marks)

Q27.(a) The graphs, A, B and C, show how the current through a component varies with the

potential difference (p.d.) across the component.

Draw a line to link each graph to the correct component.Draw only three lines.

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(2)

(b) Each of the circuits, J, K and L, include two diodes.

In which one of the circuits, J, K or L, would the filament lamp be on?

______________________________(1)

(Total 3 marks)

Q28.A circuit was set up as shown in the diagram.

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(a) Each cell provides a potential difference of 1.5 volts.

(i) What is the total potential difference provided by the four cells in the circuit?

______________________________________________________________

Total potential difference = _______________ volts(1)

(ii) What will be the reading on the voltmeter?

______________________________________________________________(1)

(b) The current through the lamp is 0.20 amps.The current through the resistor is 0.10 amps.

What is the reading on the ammeter?

___________________________________________________________________

Reading on ammeter = _______________ amps(1)

(c) Use a phrase from the box to complete the following sentence.

greater than equal to smaller than

The resistance of the lamp is ______________________________ 60 Ω.


___________________________________________________________________

___________________________________________________________________(2)

(Total 5 marks)

Q29.

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The drawing shows three identical cells and two identical lamps joined in a circuit.

(a) Use the correct symbols to draw a circuit diagram for this circuit.

(3)

(b) Each of the cells provides a potential difference (voltage) of 1.5 volts. What is the total potential difference (voltage) provided by all three cells?

__________________________________________________________ volts(1)

(c) Complete this sentence by crossing out the two lines in the box that are wrong.

The current through lamp 2 will be the current through lamp 1.(1)

(Total 5 marks)

Q30.(a) Draw lines to join the picture to the correct circuit symbol. The lamp has been done

for you.

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(2)

(b) A family tent is to be fitted with a simple lighting circuit.

The diagram shows the first circuit used.

(i) Are the lamps connected in series or in parallel?

______________________________________________________________(1)

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(ii) This is not a good circuit for using in the tent. Why?

______________________________________________________________

______________________________________________________________(1)

The diagram shows the second circuit used.

(iii) Give two reasons why this circuit is better than the first circuit.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________(2)

(Total 6 marks)

Q31.(a) (i) Complete the sentence by choosing the correct word from the box.

electrons neutrons protons

An electric current is a flow of __________________________________(1)

(ii) What is the name and circuit symbol for the instrument used to measure electric current?

Name: ____________________________________________________

Symbol:

(2)

(b) When an electric current flows through a wire, the wire will get hot. Two of the following make use of this heating effect. Which two?

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1. _________________________________________________________________

2. _________________________________________________________________(2)

(Total 5 marks)

Q32.The diagram shows a circuit.

(a) (i) Name component X. _____________________________

(ii) What does meter Y measure? ______________________

(iii) What does meter Z measure? ______________________(3)

(b) Which of the equations shows how current, potential difference and resistance are related?

Tick the box against the correct equation.

current = potential difference × resistance


resistance = current × potential difference (1)

(Total 4 marks)

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Q33.(a) The diagram shows a simple circuit. Add an ammeter and a voltmeter to the circuit

to show how to measure the current through the fixed resistor and the voltage across it.

(2)

(b) An experiment using a circuit like the one above was set up. The following results were obtained when the resistance of the variable resistor was decreased.

(i) Draw a graph of the results below.

Voltage across fixed resistorin volts

Current in amps

0.500.751.001.25

0.100.150.200.25

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(2)

(ii) Use the graph to find the voltage when the current is 0.05 A.

Voltage =____________________ V(1)

(Total 5 marks)

Q34.The circuit contains two cells, an ammeter and a lamp. The reading on the ammeter is 0.2 A.

(a) What will be the reading on the ammeters in each of the circuits below?

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(i) Current is __________ A (ii) Current is __________ A(2)

(b) An ammeter was in a series circuit with two cells and a variable resistor.

The ammeter showed a reading of 0.3 A.

(i) Draw a circuit diagram for the circuit.

(2)

(ii) What will happen to the reading on the ammeter if the resistance of the variable resistor is increased?

______________________________________________________________(1)

(Total 5 marks)

Q35.The circuit contains three identical lamps.

(a) Complete each of the sentences about the circuit, using one of the phrases in the box.

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more than less than the same as

(i) The current at A is ______________________________ the current at B.(1)

(ii) The current at A is ______________________________ the current at D.(1)

(iii) The current at F is _______________________________ the current at E.(1)

(iv) The current at F is ______________________________ the current at D.(1)

(b) In the circuit, which lamp is brightest? _______________


___________________________________________________________________

___________________________________________________________________(2)

(Total 6 marks)

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