A laboratory ammeter shows the current through a resistor as and the colour code on…

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

A laboratory ammeter shows the current through a resistor as

0.25\,\text{A}

and the colour code on the resistor reads

40\,\Omega

. Which one of the following expressions would give the power dissipated in the resistor with the least algebraic manipulation? (a)

P = VI

(b)

P = \dfrac{V^{2}}{R}

(c)

P = I^{2} R

(d)

P = \dfrac{1}{2}\,I^{2}R