Question 39
Current ElectricityA cell of internal resistance 2 ohms supplies current to a 6-ohm resistor. The efficiency of the cell is
- A.12.0%
- B.25.0%
- C.33.3%
- D.75.0%
Show the answer and explanation
Answer: D (75.0%)
Explanation
Efficiency = useful power ÷ total power = R/(R + r) = 6/8 = 75%.