The difference of potential between the terminals of cells is 2.2 volts. When a 4ohm resistor is connected across the terminals of this cells, the potential difference is 2 volts. What is the internal resistance of the cell?
-
A.
0.10 ohms -
B.
0.25ohms -
C.
0.40ohms -
D.
2.50ohms -
E.
4.00ohms
Correct Answer: Option C
Explanation
IR = 2 and Ir = 0.2
I = (frac{2}{R}) ; I = (frac{0.2}{r})
(frac{2}{4}) = (frac{0.2}{r})
r = 0.4(Omega)