Step 1:

The emf of the battery is $\"\"$ .

The internal resistance of the cell is $\"\"$

The delivering current is $\"\"$ .

Suppose that the battery with emf $\"\"$ and internal resistance $\"\"$ supplies a current $\"\"$ through an external load resistor $\"\"$ ,

then the potential difference across the battery is $\"\"$ .

Substitute $\"\"$ , $\"\"$ and $\"\"$ in $\"\"$ .

$\"\"$

Potential difference across the battery is $\"\"$ .

Solution:

Potential difference across the battery is $\"\"$ .