When a resistance R is across a cell, the voltage across the terminals of the cell is reduced to two-third of its normal value. The internal resistance of the cell is
-
A.
(frac{2}{1})R -
B.
(frac{1}{2})R -
C.
(frac{3}{2})R -
D.
5R
Correct Answer: Option B
Explanation
IR = (frac{2}{3}) I(R + r)
r = (frac{1}{2})R