In the same parallel circuit, what is the power dissipated by the 6 Ω resistor?

In the same parallel circuit, what is the power dissipated by the 6 Ω resistor?

• A. 4800 W
• B. 2400 W
• C. 3600 W
• D. 1200 W

Answer: (B)

In a parallel circuit, the full source voltage appears across every branch, so the 6 Ω resistor has the same voltage across it as the rest of the network. The power dissipated by a resistor can be found with P = V^2 / R. If the supply is 120 volts, then the power in the 6 Ω resistor is P = (120)^2 / 6 = 14400 / 6 = 2400 watts. You can also see it by finding the current: I = V / R = 120 / 6 = 20 A, and then P = I^2 R = 20^2 × 6 = 400 × 6 = 2400 W, or P = VI = 120 × 20 = 2400 W. Therefore, the power dissipated by the 6 Ω resistor is 2400 W.

In a parallel circuit, the full source voltage appears across every branch, so the 6 Ω resistor has the same voltage across it as the rest of the network. The power dissipated by a resistor can be found with P = V^2 / R. If the supply is 120 volts, then the power in the 6 Ω resistor is P = (120)^2 / 6 = 14400 / 6 = 2400 watts. You can also see it by finding the current: I = V / R = 120 / 6 = 20 A, and then P = I^2 R = 20^2 × 6 = 400 × 6 = 2400 W, or P = VI = 120 × 20 = 2400 W. Therefore, the power dissipated by the 6 Ω resistor is 2400 W.