A 4.50-volt personal stereo uses 1950 joules of electrical energy in one hour. what is the electrical resistance of the personal stereo?

Question

asked Oct 5, 2019 44.9k views

1 Answer

Volley · Answer 1 · 2019-10-12T01:33:44+0000

The stereo uses an energy of
E=1950 J

in a time

, therefore the power of the stereo is given by

P= (E)/(t)= (1950 J)/(3600 s)=0.54 W

We also know that the power of an electrical device is related to its voltage, V, and its resistance, R, by the following equation

P= (V^2)/(R)

therefore, we can rearrange the equation to calculate the resistance of the stereo:

$R= (V^2)/(P)= ((4.5 V)^2)/(0.54 W)=37.5 \Omega$