Remembering Ohm's law, we can replace either Voltage or Current to produce two further formulas for power these can be summarised in the diagram below.

Power is defined as "The amount of energy used per second". It is measured in units of Watts (W) or Joules per second.

Remember that Voltage is the energy given to every coulomb of charge and that current is how much charge flows every second. Combining this knowledge with the formula above gives us another formula for power.