A cell has an open circuit voltage V1 and a closed circuit voltage V2 when a current is flowing through it. Therefore, the internal resistance of the cell is
-
A.
(frac{V_2}{I}) -
B.
(frac{V_1}{I}) -
C.
(frac{(V_1 + V_2)}{I}) -
D.
(frac{(V_1 – V_2)}{I}) -
E.
(frac{(V_2 – V_1)}{I})
Correct Answer: Option E
Explanation
On open circuit, V1 = I; On closed circuit V2 = IR + Ir
V2 = V1 + Ir
r = (frac{(V_2 – V_1)}{I})