Voltage is measured in units of volts, resistance is measured in units of ohms, current is measured in units of amps and electrical power is measures in watts.

Voltage (V) = current (I) multiplied by resistance (r) is a basic formula of physics called Ohms law.

Increasing either current or voltage will increase electrical power. It is much like using a garden hose. If you increase either the amount of water flowing through the hose or the amount of pressure pushing the water through the hose, the force of the water will increase.

More Info: science.howstuffworks.com