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...

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?

Answer Details

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$\Omega$