Question

A circuit has a voltage of 24 V and a current of 40 mA. What is the power of the circuit?

A. 6 W
B. 9.6 W
C. 6.24 W
D. 0.96 W

Answer 1

Hi! There is a relation between voltage, current, and power. It's very simple, too! It's voltage multiplied times current.

`P=IV`
or
`VI=P` might be easy to remember because V.I.P. (like V.I.P. stadium seating)

Then you just have to work with units to get watts. Watts is volt-amps.

You can convert at any point to get watts as the unit. I'll turn the current to amps first.

`40\text {mA}\cdot\frac{1\text A}{1000\text{mA}}=0.040\text A`
Then, multiply
`VI=P`

`24\text V\cdot0.040\text A=0.96\text V\cdot\text A = 0.96\text W`