The difference of potential between the terminals of cell...
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?
0.10 ohms
0.25 ohms
0.40 ohms
2.50 ohms
4.00 ohms
Correct answer is C
IR = 2 and Ir = 0.2
I = 2R ; I = 0.2r
24 = 0.2r
r = 0.4Ω