Question #b9556

Jan 14, 2017

$P = I \cdot V = \left(0.400 A\right) \left(12.0 V\right) = 4.80$ watts

Explanation:

Withe the information you have, you could also use

$P = {I}^{2} R$ or $P = {V}^{2} / R$

all will yield the same result.

Jan 14, 2017

$4.8 W$

Explanation:

$P = V \times I$ where $V = 12.0$ and $I = 0.400$. $12.0 \times 0.400 = 4.8$.
You could also have said that $P = {V}^{2} / R$ giving ${12}^{2} / 30 = 4.8$.
Also the question is slightly over-specified, in that you could have deduced the current (assuming that the resistor obey's Ohm's Law) from $I = \frac{V}{R} = \frac{12}{30} = 0.4$