The power dissipated in the unknown resistor (R) is
A) 4 W
B) 6 W
C) 8 W
D) 2 W
E) 10 W

Question

The power dissipated in the unknown resistor (R) is
A) 4 W 
B) 6 W 
C) 8 W 
D) 2 W 
E) 10 W

Quizplus · Accepted Answer

Using the formula for power dissipated in a resistor, P = V^2/R, we can calculate the power dissipated in the known resistor, P1 = 16/4 = 4 W.

Since the circuit is a series circuit, the same current flows through each resistor. Therefore, the voltage drop across the unknown resistor (R) is V2 = 16 - 8 = 8 V.

Using the same formula for power, we can calculate the power dissipated in the unknown resistor:

P2 = V2^2/R

Substituting in the values we know:

8 = 8^2/R

Solving for R:

R = 8^2/8 = 8 W

Therefore, the power dissipated in the unknown resistor (R) is 8 W, choice C.

The Power Dissipated in the Unknown Resistor (R) Is