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
Verified Correct Answer: B.
Physical Principles & Numerical Solution
IR = \(\frac{2}{3}\) I(R + r)
r = \(\frac{1}{2}\)R
Source: Myschool Past Questions Archive (Record #28393)