Question

A circuit has a voltage drop of 12.0 V across a 30.0 resistor that carries a current of 0.400 A. What is the power used by the resistor? Use P = VI.

A. 360.0 W
B. 12.0 W
C. 4.80 W
D. 57.0 W

Answer 1

P=VI
P=12.0×0.400
P=4.80 Watt
So C is right

Answer 2

Option ( c ) is correct.

Using the formula for power

`P= i^2 R`

P= power

i= current= 0.4 A

R= resistance= 30 ohm

so power= (0.4)² (30)

Power=4.8 W