Question

The power rating of a resistor is 0.80 W. If the value of the resistor is 400 Ω, what is the maximum current it can draw

I know the answer is 45 but how

Answer 1

Step-by-step explanation:

The answer is NOT just 45...it is 45 mAmps

POWER = .80 watts

POWER = I * V but V = I R

so POWER = I * IR = I^2 R

.80 W = I^2 * (400 Ω) <======solve for I

I = .0447 AMPS = 44.7 mAmps = (rounded ) 45 mAmps