A cell of internal resistance 2 ohms supplies current to a 6 ohms resistor. The efficiency of the cell is
-
A.
12.0% -
B.
25.0% -
C.
33.3% -
D.
75.0%
Correct Answer: Option D
Explanation
Efficiency = (frac{IR}{I(R + r)}) x 100
= (frac{6}{I(2 + 6)}) x 100
= 75%