Question

How much power is used by a 12.0-v car battery that draws 0.5 a of current?

Answer 1

The electric power used by the car battery is given by

`P=VI`

where
V is the voltage of the battety
I is the current
P is the electric power.

For the battery in our problem, the voltage is V=12.0 V while the current intensity is I=0.5 A, so the power used by the battery is

`P=VI=(12.0 V)(0.5 A)=6.0 W`