A cell can be balanced again 110 cm and 100 cm of potentiometer wire, respectively with and without being short circuited through a resistance of 10$\Omega$. Its internal resistance is :

Question

$\begin {array} {1 1} (1)\;Zero & \quad (2)\;1.0\: ohm \\ (3)\;0.5\: ohm & \quad (4)\;2.0\: ohm \end {array}$