How much power is produced if a voltage of 4 V is applied to a circuit with a resistance of 64 Omega?

1 Answer
Jun 22, 2016

P = 0.25 W
*W stands for Watts

Explanation:

You have two given quantities:
-Voltage (V) and
-Resistance (R).

Then we use the following equations:
(1) V = I R
and
(2) P = I V

we can do solve the problem in two ways:
(A) solve for I and plug it into (2) or (B) we could plug in I from (1) and having the expression:

(3) P= V^2 /R

Lets first do (A):

(A.1) I = V/R
then lets plug in V and R
(A.2) I = (4V)/(64Omega)
(A.2.1)I = 0.125 Amps
then plug in (A.2.1) in (2)
(A.3) P = (0.125 Amp)*(4 V)
(A.3.1) P = 0.25W

then (B):
(B.1) P = (4V)^2/(64 Omega) = (16V^2)/(64 Omega)
(B.1.1) P = 0.25 W

Hope this helps!