Question 28
Electrical Energy and PowerIn the diagram above, if each of the resistors can dissipate a maximum of 18W without becoming excessively heated, what is the maximum power that circuit can dissipate?
- A.27W
- B.18W
- C.9W
- D.5W
Show the answer and explanation
Answer: A (27W)
Explanation
The series 2 Ω resistor carries the full current: 18 = I2 × 2 gives I = 3 A. Total resistance = 2 + 1 = 3 Ω, so P = I2R = 9 × 3 = 27 W.