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WorksheetsP5 Electricity in the home
Total questions: 27
Worksheet time: 14mins
What type of current is produced by a cell or a battery?
Alternating current (ac)
Direct current (dc)
Alternating potential difference
Step-up transformer
What is the frequency of the mains electricity supply in the UK?
50 Hz
60 Hz
230 Hz
400 Hz
What is the voltage of the mains electricity supply in the UK?
110 V
230 V
400 V
50 V
What is the purpose of a fuse in an electrical plug?
To increase the current if there is a fault
To decrease the voltage
To break the circuit if there is a fault
To store electrical energy if there is a fault
Why do transformers improve efficiency in power transmission?
They increase the current in the cables
They decrease the potential difference
They reduce the power lost as heat
They increase the resistance in the cables
What is the equation for power in terms of current and potential difference?
P = IV
P = IR
P = I^2R
P = V^2/R
What is the role of step-up transformers in the National Grid?
To decrease the potential difference
To increase the potential difference
To decrease the current
To increase the resistance
What is the role of step-down transformers in the National Grid?
To increase the potential difference
To decrease the potential difference
To increase the current
To decrease the resistance
The equation to calculate charge flow is (a)
The equation to find the energy transferred to an electrical appliance when charge flows through it is (a)
The equation to find the energy transferred by an electrical appliance using power is (a) .
Why is the current provided by a cell called a direct current (d.c.)?
It only flows in one direction
It flows in multiple directions
It changes direction periodically
It does not flow at all
What is an alternating current (a.c.)?
Current that flows in one direction
Current that repeatedly reverses direction
Current that does not flow
Current that flows in a circular path
What kind of current is supplied by mains electricity?
Direct current
Alternating current
Static current
Pulsating current
What is the frequency and voltage of mains electricity?
60 Hz, 120 V
50 Hz, 230 V
40 Hz, 220 V
70 Hz, 240 V
What colours are the live, neutral, and earth wires in a three-core cable?
Live = red, neutral = black, earth = white
Live = brown, neutral = blue, earth = green and yellow stripes
Live = yellow, neutral = green, earth = blue
Live = blue, neutral = brown, earth = green
What is the function of the live wire in a three-core cable?
Completes the circuit
Carries the alternating potential difference from the supply
Safety wire to stop the appliance becoming live
Provides grounding
What is the function of the neutral wire in a three-core cable?
Completes the circuit
Carries the alternating potential difference from the supply
Safety wire to stop the appliance becoming live
Provides grounding
What is the function of the earth wire in a three-core cable?
Completes the circuit
Carries the alternating potential difference from the supply
Safety wire to stop the appliance becoming live
Provides grounding
When is there a current in the earth wire?
When there is a fault
When the appliance is turned on
When the appliance is turned off
When the circuit is complete
Why is the live wire dangerous?
It provides a large p.d. that would cause a large current to flow through a person if they touched it
It provides a small p.d. that would cause a small current to flow through a person if they touched it
It is not insulated
It is always grounded
What is the National Grid?
A local network of cables and transformers
A nationwide network of cables and transformers that link power stations to customers
A system of underground cables
A network of solar panels
What are step-up transformers used for in the National Grid?
Increase the p.d. from the power station to the transmission cables
Decrease the p.d. from the power station to the transmission cables
Increase the current from the power station to the transmission cables
Decrease the current from the power station to the transmission cables
What are step-down transformers used for in the National Grid?
Increase the p.d. from the transmission cables to the mains supply in buildings
Decrease the p.d. from the transmission cables to the mains supply in buildings so that it is safe to use
Increase the current from the transmission cables to the mains supply in buildings
Decrease the current from the transmission cables to the mains supply in buildings
How does having a large potential difference in the transmission cables help to make the National Grid an efficient way to transfer energy?
Large p.d. means a large current is needed to transfer the same amount of power
Large p.d. means a small current is needed to transfer the same amount of power, small current in the transmission cables means less electrical power is wasted due to heating
Large p.d. means a small current is needed to transfer the same amount of power, large current in the transmission cables means more electrical power is wasted due to heating
Large p.d. means a large current is needed to transfer the same amount of power, small current in the transmission cables means more electrical power is wasted due to heating
What two things does energy transfer to an appliance depend on?
Power of appliance, time it is switched on for
Voltage of appliance, time it is switched on for
Current of appliance, time it is switched on for
Resistance of appliance, time it is switched on for
What are the units for power, current, potential difference, and resistance?
Watts (W), amps (A), volts (V), ohms (Ω)
Joules (J), amps (A), volts (V), ohms (Ω)
Watts (W), coulombs (C), volts (V), ohms (Ω)
Joules (J), coulombs (C), volts (V), ohms (Ω)
