Electrical current transfers energy around circuits. The power is the rate at which a circuit transfers energy.
How much energy is transferred by a 250 W television set in 4 minutes?
If 25 C of charge shifts 50 J of energy between two points, what is the voltage between those points?
What power is transmitted by a current of 2 A in a resistor with a potential difference across it of 5 V?
What power is transmitted by a current of 2 A in a 6 Ω resistor?
What is the power output of a mains transformer with a current of 0.2 A passing through it?
The power input into a transformer of 100 per cent efficiency is 2,000 W. What will the power output be?
Less than 2,000 W
More than 2,000 W
The power input of a transformer is 1,200 W and the output voltage is 120 V. What will the output current be?
How is electricity transmitted across the UK?
At a high current and a low voltage
At a high current and a high voltage
At a high voltage and a low current
Why is electricity transmitted around the country at 400,000 V?
Electricity is generated at 400,000 V
This reduces the heating effect of the current in the transmission wires
Some large factories need to operate at 400,000 V
If a 6 V cell transfers 36 J of energy around a circuit, how much charge has flowed?