Energy (E) is measured in joules (J).
Power (P) is measured in watts (W). Power is the rate at which energy is transferred. One watt is equal to one joule per second ( 1 W = 1 J s-1 ).
- E = energy in joules, J
- V = potential difference in volts,V
- I = current in amperes, A
- t = time in seconds, s
- P = power in watts, W
- V = potential difference in volts, V
- I = current in amperes, A
- P = power in watts, W
- I = current in amperes, A
- R = resistance in ohm’s, W
Examples;
Q1) How much energy is dissipated by a resistor if a potential difference of 9.0V is applied to it for 331 seconds and a current of 0.23 A flows through it?
Q2) What is the current flowing through a bulb if it has a power of 100W when the potential difference supplied to it is 230V?
Q3) What is the power dissipated by a 32 ohm resistor when a current of 1.4 A flows through it?
