Electrical energy

For a given amount of electrical charge that moves, the amount of energy transferred increases as the potential difference increases.

Calculating energy transferred

Work out the energy transferred using this equation:

curriculum-key-fact
energy = current x voltage x time

E = I × V × t

where:

E is the energy transferred in joules, J

I is the current in amperes, A

V is the potential differences in volts, V

t is the time in seconds, s

For example, how much energy is transferred in two seconds with a current of 1 ampere and a potential difference of 120 volts.

E = 1 × 120 × 2

= 240 J

Charge is current multiplied by time so this equation can also be written as:

E = V × Q

where:

E is the energy transferred in joules, J

V is the potential difference in volts, V

Q is the charge in coulombs, C

For example, how much energy is transferred when the potential difference is 120 V and the charge is 2 C?

Energy transferred

= 120 × 2

= 240 J