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Electricity warm up

Total questions: 177

Worksheet time: 3hrs 53mins

Name
Class
Date
1.

What is the best definition for current.

a)

the flow of charge.

b)

how much charge flows past a point in a unit of time.

c)

how much charge there is around the circuit.

d)

the energy used by charge as it flows.

2.

A current of 1.5 A flows for a time and a total of 15 C of charge flows past each point in a circuit. How long does the current flow?

a)

22.5 s

b)

10 s

c)

0.1 s

d)

16.5 s

3.

How should an ammeter be connected to measure the current through a bulb?

a)

In series with the bulb.

b)

In parallel with the bulb.

c)

It doesn't matter, you'll always get the same reading.

4.

potential difference (Voltage) can be calculate from...

a)

Voltage = Energy x Charge

b)

Voltage = Energy x Current

c)

Voltage = Energy / Charge

d)

Voltage = Energy / Current

5.

What is the voltage across a light bulb if it uses 100 J of energy per second and 0.5 coulombs of charge per second.

(a)  

6.

What is the relationship between potential difference, current and resistance across a component.

a)

V = I/R

b)

I = V x R

c)

V = R/I

d)

V = I x R

7.

What is the resistance of the R2 resistor if the current is 0.8 A in ohms? (value only needed, no units.

(a)  

8.

What is the value of the voltage (V1)? (value only needed, no units.

(a)  

9.

Which type of circuit is better in a situation where you need to control several lights individually with different switches, but they all run off the same power supply?

a)

Series

b)

Parallel

c)

Either.

d)

Neither.

10.

What is the unknown current at this wire junction? value and units.

(a)  

11.

What is the voltage on the 75 ohm resistor (V1)?

a)

187.5 V

b)

120 V

c)

93.75 V

d)

60 V

12.

What is the current through the 75 ohm resistor (V1)?

(a)  

13.

A student measures the current across a component as the voltage is increased. What is this component most likely to be?

a)

A commercial resistor.

b)

A Thermistor.

c)

An LDR.

d)

A light bulb.

e)

A wire in a water bath.

14.

As the gradient of the graph line decreases this shows that the resistance is...

a)

decreasing.

b)

staying constant.

c)

increasing.

d)

the line has nothing to do with resistance.

15.

The formula for electrical power is.

a)

P = I x V

b)

P = V/I

c)

P = V/R

d)

P = I x R

e)

P = I/R

16.

The units for electrical power are? (one word needed)

(a)  

17.

A light bulb runs on 12 V and 0.8 A what is the input power? (no unit needed).

(a)  

18.

If each cell provides a potential difference of 1.5 volts.What is the total potential difference provided by the four cells in the circuit?

(a)  

19.

In the circuit what is the name of the component labelled X?

a)

Variable Resistor

b)

Light-Dependent resistor

c)

Thermistor

d)

Resistor

20.

Varying the voltage across a component and measuring the current a student collected some results.

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

Which one of the following is the most likely cause of the anomalous result on this graph?

a)

The resistance of the resistor changed.

b)

The student misread the ammeter.

c)

The Voltmeter had a zero error.

d)

The ammeter had a zero error.

e)

They didn't allow time for charge to build up in the circuit.

21.

Varying the voltage across a component and measuring the current a student collected some results.

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

What is the resistance of this component in ohms? (value only needed)

(a)  

22.

What is the component with the voltmeter across it?

a)

A resistor

b)

A variable resistor

c)

An LDR

d)

A Thermistor

23.

The current in the circuit is 3.5 mA when the potential difference across the thermistor is 4.2 V


Calculate the resistance of the thermistor in ohms. (value only needed).

(a)  

24.

What will happen to the voltage reading if the temperature on the thermistor increases?

a)

it increases

b)

it decreases

c)

it stays the same

25.

Which graph shows the IV graph for a Diode?

a)
b)
c)
26.

The ammeter displays a reading of 0.10 A.Calculate the potential difference across the 45 Ω resistor.

(a)  

27.

The ammeter displays a reading of 0.10 A.

Calculate the resistance of the resistor labelled R in ohms. (no units needed)

(a)  

28.

State what happens to the total resistance of the circuit and the current through the circuit when switch S is closed.

a)

The resistance decreases and the current decreases

b)

The resistance increases and the current increases

c)

The resistance increases and the current decreases

d)

The resistance decreases and the current increases

29.

If switch S is open (as in the diagram), what is the power used by the 60 ohm resistor? The current in the circuit is 0.1 A.

(a)  

30.

If two circuits are constructed both with two 60 ohm light bulbs and a 12 V power supply.

What is true of the total power in each circuit?

a)

The same.

b)

Less in parallel.

c)

Double in parallel.

d)

Four times greater in parallel.

31.

When the light intensity on an LDR increases then its resistance...

a)

Stays the same

b)

Increases

c)

Decreases

32.

How should an ammeter be connected to measure the current through a bulb?

a)

In series with the bulb.

b)

In parallel with the bulb.

c)

It doesn't matter, you'll always get the same reading.

33.

A student measures the current across a component as the voltage is increased. What is this component most likely to be?

a)

A commercial resistor.

b)

A Thermistor.

c)

An LDR.

d)

A light bulb.

e)

A wire in a water bath.

34.

As the gradient of the graph line decreases this shows that the resistance is...

a)

decreasing.

b)

staying constant.

c)

increasing.

d)

the line has nothing to do with resistance.

35.

This is the symbol for a...

a)

Motor

b)

Ammeter

c)

Bulb

d)

Voltmeter

36.

This is the symbol for a...

a)

Light Dependent Resistor

b)

Light Emitting Diode

c)

Thermistor

d)

Cell

37.

This is the symbol for a...

a)

Fuse

b)

Wire

c)

Light Emitting Diode

d)

Heater

38.
A material in which electrons are not able to move easily is an
a)
Circuit 
b)
Insulator 
c)
Resistance 
d)
Conductor
39.
A particle that carries a negative electric charge is called a(n) ______.
a)
neutron
b)
atom
c)
proton
d)
electron
40.

Calculate the voltage across the fixed resistor.

a)

0.3 V

b)

3 V

c)

4.8 V

d)

12 V

41.

Which resistor will prevent the most current flow?

a)

1 Ω

b)

100 Ω

c)

1000 Ω

d)

0.5 Ω

42.
How does resistance affect current?
a)
less resistance - less current
b)
more resistance - less current
c)
more resistance - more current
d)
resistance does not affect current
43.

What size resistor would produce a 3A current flow if the voltage was 12V?

a)

1 Ohm

b)

3 Ohms

c)

4 Ohms

d)

12 Ohms

44.
What is current measured in?
a)
Ω (Ohms)
b)
V (Volts)
c)
A (Amps)
d)
W (Watts)
45.
What is resistance measured in?
a)
Ω (Ohms)
b)
V (Volts)
c)
A (Amps)
d)
W (Watts)
46.
If the Voltage is increased and the resistance stays the same, Current will
a)
Increase
b)
Decrease
c)
Stay the same
d)
X
47.

How do you calculate current from voltage and resistance?

a)

Current = voltage x resistance

b)

Current = resistance x power

c)

Current = voltage ÷ resistance

d)

Current = resistance ÷ voltage

48.

As the diameter of a wire increases, the resistance of the wire will

a)

increase

b)

decrease

c)

stay the same

49.

As the length of a wire increases, the resistance of the wire will

a)

increase

b)

decrease

c)

stay the same

50.

If the current through a resistor is 2A and the voltage across it is 12V, what is the resistance

a)

12Ω

b)

6Ω

c)

24Ω

d)

0.167Ω

51.

What is the unit of current?

a)

Ohm

b)

Ampere (A)

c)

Joule

d)

Volt

52.

State Ohm's Law.

a)

V = R / I

b)

R = V * I

c)

V = I * R

d)

I = V / R

53.

Calculate the resistance if the potential difference is 12V and the current is 3A.

a)

2 ohms

b)

8 ohms

c)

6 ohms

d)

4 ohms

54.

What happens to the current in a circuit if the resistance is increased?

a)

The current in the circuit becomes negative.

b)

The current in the circuit remains the same.

c)

The current in the circuit decreases.

d)

The current in the circuit increases.

55.

Define potential difference.

a)

The speed of electrons between two points in an electric field

b)

The resistance between two points in an electric field

c)

The amount of charge between two points in an electric field

d)

The difference in electric potential energy between two points in an electric field.

56.

Fill in the blank: Resistance is measured in ________.

a)

Volts

b)

Amps

c)

Ohms

d)

Watts

57.

In a series circuit, how does the total resistance compare to individual resistances?

a)

Total resistance is unrelated to individual resistances.

b)

Total resistance is greater than the sum of individual resistances.

c)

Total resistance is equal to the sum of individual resistances.

d)

Total resistance is less than the sum of individual resistances.

58.

What is the formula to calculate power in a circuit?

a)

P = V + I

b)

P = V * I

c)

P = V / I

d)

P = V ^ I

59.

Explain the relationship between current and resistance in a circuit.

a)

Current and resistance in a circuit are inversely proportional according to Ohm's Law.

b)

Current and resistance in a circuit have no relationship.

c)

Current and resistance in a circuit are directly proportional according to Ohm's Law.

d)

Current and resistance in a circuit are only related in AC circuits.

60.

What is the purpose of a resistor in an electrical circuit?

a)

To limit the flow of current in an electrical circuit.

b)

To store energy in an electrical circuit.

c)

To amplify the signal in an electrical circuit.

d)

To increase the voltage in an electrical circuit.

61.

True or False: Current is the flow of electrons in a circuit.

a)

Absolutely

b)

False

c)

True

d)

Yes

62.

Calculate the current if the resistance is 4 ohms and the potential difference is 8V.

a)

2A

b)

4A

c)

10A

d)

6A

63.

What is the symbol for resistance in a circuit diagram?

a)

zigzag line

b)

straight line

c)

square

d)

circle

64.

How does the resistance of a wire change if its length is doubled?

a)

The resistance will double.

b)

The resistance will halve.

c)

The resistance will decrease.

d)

The resistance will remain the same.

65.

What is the SI unit of resistance?

a)

Ampere

b)

Volt

c)

Ohm (Ω)

d)

Joule

66.

Explain how the potential difference affects the current in a circuit.

a)

The potential difference has no impact on the current in a circuit

b)

Increasing the potential difference decreases the current

c)

The potential difference affects the current in a circuit by increasing or decreasing it proportionally.

d)

Decreasing the potential difference increases the current

67.

Fill in the blank: The potential difference across a component is measured in ________.

a)

volts

b)

ohms

c)

watts

d)

amperes

68.

What is the relationship between potential difference and current in a circuit?

a)

Potential difference is inversely proportional to current.

b)

Potential difference has no effect on current.

c)

Current in a circuit is constant regardless of potential difference.

d)

Current in a circuit is directly proportional to potential difference.

69.

What happens to the current if the potential difference is doubled in a circuit?

a)

The current will double.

b)

The current will halve.

c)

The current will quadruple.

d)

The current will remain the same.

70.

Describe the behavior of current in a parallel circuit.

a)

The behavior of current in a parallel circuit is that it splits up and flows through each branch independently.

b)

The behavior of current in a parallel circuit is that it combines and flows through all branches simultaneously.

c)

Current in a parallel circuit always follows the path of least resistance.

d)

In a parallel circuit, current only flows through one branch at a time.

71.

In a series circuit...

a)

the current is the same everywhere.

b)

the current is split between components.

c)

the voltage is the same everywhere.

d)

the voltage is split between components.

72.

Ammeters should always be connected in (a)   .

73.

In parallel circuits...

a)

the current is the same everywhere.

b)

the current splits at a junction.

c)

the voltage is the same everywhere.

d)

the voltage splits at a junction.

74.

In a series circuit, if one component breaks the others will remain on.

a)

True

b)

False

75.

What is the missing value on the voltmeter?

(a)  

76.

What is the missing value on the ammeter?

(a)  

77.

What is the reading on the labelled ammeter?

(a)  

78.

Voltmeters should always be connected in (a)   around a component.

79.

Potential difference is another word for (a)   .

80.
what is this symbol for?
a)
light bulb
b)
switch
c)
battery
d)
resistor
81.
A series circuit has how many pathways for the electrons to flow?
a)
Two
b)
One
c)
Many
d)
Zero
82.
What is one problem with using a series circuit? 
a)
It has a lot of series. 
b)
If one light goes down, they all go down! 
c)
It doesn't work properly.
d)
There are no problems. 
83.
What is a benefit of using a parallel circuit?  
a)
It gets confusing.
b)
There are no problems.
c)
If one light goes out, it does not affect the others. 
d)
If one light goes out, they all go out. 
84.
In most electrical circuits, the pathway is made of:
a)
Wood
b)
Plastic
c)
Metal
d)
Static
85.
What kind of circuit is this?
a)
Series
b)
Consecutive
c)
Parallel
d)
Training
86.
What kind of circuit is this?
a)
Series
b)
Consecutive
c)
Parallel
d)
Training
87.
If the voltage across the battery was 10V in this diagram. What would the voltage across each bulb be?
a)
10V
b)
5V
c)
20V
d)
0V
88.
Which of the two circuits would have the brightest bulbs? 
a)
A
b)
B
89.
A voltmeter is described as a device that can be used to measure
a)
Voltage
b)
Current
c)
Resistance
d)
Power
90.
This circuit does not work because…
a)
the bulbs are not connected properly
b)
two cells are not powerful enough
c)
there is a break in the circuit
d)
the cells are facing each other
91.
This circuit does not work because…
a)
the bulbs are not connected properly
b)
the single cell is not powerful enough
c)
there is a break in the circuit
d)
there is a short crcuit
92.
a)
Circuit X is brighter than circuit Y
b)
Circuit Y is brighter than circuit X
c)
Both circuits have the same brightness
d)
Neither circuit will light the bulbs
93.
a)
X = OFF
Y = OFF
b)
X = ON
Y = OFF
c)
X = OFF
Y = ON
d)
X = ON
Y = ON
94.

What is the current at point a?

a)

a=0.4A

b)

a=0.2A

c)

a=1.0A

d)

a=0.6A

95.

This is the symbol for a...

a)

Motor

b)

Ammeter

c)

Bulb

d)

Voltmeter

96.

This is the symbol for a...

a)

Thermistor

b)

Bulb

c)

Fixed Resistor

d)

Ammeter

97.

This is the symbol for a...

a)

Light Dependent Resistor

b)

Light Emitting Diode

c)

Thermistor

d)

Cell

98.

This is the symbol for a...

a)

Light Emitting Diode

b)

Fuse

c)

Fixed Resistor

d)

Variable Resistor

99.

This is the symbol for a...

a)

Bulb

b)

Voltmeter

c)

Ammeter

d)

Motor

100.

This is the symbol for a...

a)

Light Emitting Diode

b)

Light Dependent Resistor

c)

Fuse

d)

Cell

101.

This is the symbol for a...

a)

Fuse

b)

Cell

c)

Fixed Resistor

d)

Variable Resistor

102.

This is the symbol for a...

a)

Fuse

b)

Wire

c)

Light Emitting Diode

d)

Heater

103.

This is the symbol for a...

a)

Wire

b)

Motor

c)

Variable Resistor

d)

Thermistor

104.

This is the symbol for a...

a)

Motor

b)

Thermistor

c)

Fuse

d)

Battery

105.

This is the symbol for a...

a)

Battery

b)

Thermistor

c)

Motor

d)

Fuse

106.

This is the symbol for a...

a)

Thermistor

b)

Fixed Resistor

c)

Variable Resistor

d)

Fuse

107.

This is the symbol for a...

a)

Fixed Resistor

b)

Variable Resistor

c)

Light Dependent Resistor

d)

Fuse

108.

The graph shows the change in current with potential difference for

a)

an LED

b)

a filament lamp

c)

a diode

d)

a thermistor

109.

To calculate the resistance of the component at a particular potential difference you

a)

read the current at that point on the graph and calculate p.d divided by current

b)

draw a tangent to the line at that point and calculate the gradient

c)

draw a tangent to the line at that point and calculate 1/gradient

d)

read the current at that point on the graph and calculate current/p.d

110.

The resistance of the component

a)

is always constant as the p.d. increases

b)

starts high and then decreases as the p.d. increases

c)

starts constant for low values of p.d. and then increases as the p.d. increases

d)

starts constant for low values of p.d. and then decreases as the p.d. increases

111.

Which component has the highest resistance?

a)

1

b)

2

112.

The components 1 and 2 which produced this IV graph are:

a)

Resistors

b)

Filament lamps

c)

Diodes

d)

A combination of the above

113.

Where would you place an ammeter in the circuit?

a)

Green ?

b)

Red ?

114.

Where would you place a voltmeter in the circuit?

a)

Green ?

b)

Red ?

115.

What is the relationship between the readings on Ammeters A1, A2 and A3

a)

A1 = A2 + A3

b)

A3 = A1 + A2

c)

A1 = A2 = A3

d)

A3 = A1-A2

116.

What is the relationship between the readings on Ammeters A1, A2 and A3

a)

A1 = A2 + A3

b)

A3 = A1 + A2

c)

A1 = A2 = A3

d)

A3 = A1-A2

117.

What is the relationship between the readings on Ammeters A1, A2 and A3?

a)

A1 = A2 = A3

b)

A1 = A2 - A3

c)

A3 = A1 + A2

d)

A3 = A1 - A2

118.

This is an example of a _________ circuit

a)

series

b)

parallel

119.

The reading on Voltmeter V1 is

a)

15V

b)

6V

c)

9V

d)

12V

120.

The reading on Voltmeter V2 is

a)

15V

b)

6V

c)

9V

d)

3V

121.

The reading on the voltmeter is

a)

3 V

b)

6 V

c)

12 V

d)

Can not answer as need to know the resistance of the bulb.

122.

What is the unit of measurement for resistance?

a)

Voltage

b)

Ampere

c)

Watts

d)

Ohms

123.
What is Resistance?
a)
the degree to which a circuit component opposes the passage of an electric current, causing energy dissipation
b)
How hard the energy is pushed
c)
The amount of charges that pass by a given point per second
d)
None of the above
124.

the formula to find current when the values of V and R are known is

a)

I = V2R

b)

I = V/R

c)

I = R/V

d)

I=VR

125.

which component produces an IV graph like this?

a)

resistor

b)

diode

c)

filament bulb

d)

fuse

126.

which component produces an IV graph like this?

a)

resistor

b)

diode

c)

filament bulb

d)

fuse

127.

which component produces an IV graph like this?

a)

resistor

b)

diode

c)

filament bulb

d)

fuse

128.

If a charge flows through a resistor, which of the following happens to the resistor?

a)

It gets colder

b)

It gets hotter

c)

It becomes positively charged

d)

Nothing

129.

In a filament lamp, in what form is most of the energy lost?

a)

Heat

b)

Sound

c)

Kinetic energy

d)

Radio waves

130.

What is power?

a)

The number of repetitions of squats a body-builder can perform

b)

The number of cylinders in a car

c)

The rate at which energy is absorbed

d)

The rate at which energy is transferred

131.

What is the formula for power?

a)

P = E⁄t

b)

P = t⁄E

c)

P = E⁄2t

d)

P = 2E⁄t

132.

Calculate the power of an appliance that uses 1000 joules of energy in 5 seconds.

a)

100 W

b)

200 W

c)

300 W

d)

400 W

133.

Power, potential difference and current are correctly related by which equation?

a)

P = I x V

b)

P = 2I x V

c)

P = I⁄V

d)

P = I⁄2V

134.

What is the voltage of an appliance if it uses 200 J per second when supplied with a current of 5 A?

a)

10 V

b)

20 V

c)

30 V

d)

40 V

135.

Which equation correctly shows the relationship between energy transferred, voltage and charge?

a)

E = V x Q

b)

E = 2V x Q

c)

E = V⁄Q

d)

E = Q⁄V

136.

What is the energy transferred if the voltage is 5 V and the charge is 10 C?

a)

50

b)

25

c)

50 J

d)

25 J

137.

A refrigerator does 1500 J of work in 5 seconds. What is its power?

a)

300 Watts

b)

500 Watts

c)

200 Watts

d)

100 Watts

138.

A heater transfers 1200 J of energy in 3 seconds. What is its power?

a)

400 watts

b)

200 watts

c)

600 watts

d)

800 watts

139.

A heater transfers 1200 J of energy in 3 seconds. What is its power?

a)

400 watts

b)

200 watts

c)

600 watts

d)

800 watts

140.

A fan does 200 J of work in 4 seconds. What is its power?

a)

50 Watts

b)

100 Watts

c)

200 Watts

d)

400 Watts

141.

A light bulb has a power of 60 watts. If it is used for 5 seconds, how much energy does it consume?

a)

12 J

b)

120 J

c)

300 J

d)

600 J

142.

A machine transfers 800 J of energy in 4 seconds. What is its power?

a)

200 watts

b)

100 watts

c)

400 watts

d)

600 watts

143.

A motor does 1000 J of work in 2 seconds. What is its power?

a)

500 Watts

b)

200 Watts

c)

100 Watts

d)

300 Watts

144.
a)

1.4A

b)

1.7A

c)

2.0A

d)

2.4A

145.
a)

A

b)

B

c)

C

d)

D

146.

What does the voltmeter read?

a)

2 V

b)

3 V

c)

10 V

d)

1 V

147.

What is the reading of the ammeter

a)

0.32 A

b)

0.44 A

c)

1 A

d)

0.28 A

148.

A power bank can store 5600 J of energy. When connected to a phone of power rating 2.5 W, how long will it take to charge? (Hint: Assume all energy is transferred to the phone.)

4 lines
149.

It takes roughly 380 kJ to boil a litre of water. How long will it take a 1.8 kW kettle to boil a litre of water?

4 lines
150.

A 60 W light bulb is turned on for 4 hours. How much energy does it require?

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151.

The mains voltage in the UK is 230 V. What would the current be in a 90 W power cable?

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152.

A 60 W bulb is supplied with 36 000 J of energy. How long is the bulb on for?

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153.

If a charge flows through a resistor, which of the following happens to the resistor?

a)

It gets colder

b)

It gets hotter

c)

It becomes positively charged

d)

Nothing

154.

In a filament lamp, in what form is most of the energy lost?

a)

Heat

b)

Sound

c)

Kinetic energy

d)

Radio waves

155.

What is power?

a)

The number of repetitions of squats a body-builder can perform

b)

The number of cylinders in a car

c)

The rate at which energy is absorbed

d)

The rate at which energy is transferred

156.

What is the formula for power?

a)

P = E⁄t

b)

P = t⁄E

c)

P = E⁄2t

d)

P = 2E⁄t

157.

Calculate the power of an appliance that uses 1000 joules of energy in 5 seconds.

a)

100 W

b)

200 W

c)

300 W

d)

400 W

158.

Power, potential difference and current are correctly related by which equation?

a)

P = I x V

b)

P = 2I x V

c)

P = I⁄V

d)

P = I⁄2V

159.

What is the voltage of an appliance if it uses 200 J per second when supplied with a current of 5 A?

a)

10 V

b)

20 V

c)

30 V

d)

40 V

160.

Which equation correctly shows the relationship between energy transferred, voltage and charge?

a)

E = V x Q

b)

E = 2V x Q

c)

E = V⁄Q

d)

E = Q⁄V

161.

What is the energy transferred if the voltage is 5 V and the charge is 10 C?

a)

50

b)

25

c)

50 J

d)

25 J

162.

A refrigerator does 1500 J of work in 5 seconds. What is its power?

a)

300 Watts

b)

500 Watts

c)

200 Watts

d)

100 Watts

163.

A heater transfers 1200 J of energy in 3 seconds. What is its power?

a)

400 watts

b)

200 watts

c)

600 watts

d)

800 watts

164.

A heater transfers 1200 J of energy in 3 seconds. What is its power?

a)

400 watts

b)

200 watts

c)

600 watts

d)

800 watts

165.

A fan does 200 J of work in 4 seconds. What is its power?

a)

50 Watts

b)

100 Watts

c)

200 Watts

d)

400 Watts

166.

A light bulb has a power of 60 watts. If it is used for 5 seconds, how much energy does it consume?

a)

12 J

b)

120 J

c)

300 J

d)

600 J

167.

A machine transfers 800 J of energy in 4 seconds. What is its power?

a)

200 watts

b)

100 watts

c)

400 watts

d)

600 watts

168.

A motor does 1000 J of work in 2 seconds. What is its power?

a)

500 Watts

b)

200 Watts

c)

100 Watts

d)

300 Watts

169.
a)

1.4A

b)

1.7A

c)

2.0A

d)

2.4A

170.
a)

A

b)

B

c)

C

d)

D

171.

What does the voltmeter read?

a)

2 V

b)

3 V

c)

10 V

d)

1 V

172.

What is the reading of the ammeter

a)

0.32 A

b)

0.44 A

c)

1 A

d)

0.28 A

173.

A power bank can store 5600 J of energy. When connected to a phone of power rating 2.5 W, how long will it take to charge? (Hint: Assume all energy is transferred to the phone.)

4 lines
174.

It takes roughly 380 kJ to boil a litre of water. How long will it take a 1.8 kW kettle to boil a litre of water?

4 lines
175.

A 60 W light bulb is turned on for 4 hours. How much energy does it require?

4 lines
176.

The mains voltage in the UK is 230 V. What would the current be in a 90 W power cable?

4 lines
177.

A 60 W bulb is supplied with 36 000 J of energy. How long is the bulb on for?

4 lines