A potentiometer wire of length 4 m has a resistance of 8 Q2. It is connected in series with a battery of e.m.f 2 volts and negligible internal resistance. If the e.m.f of a cell balances against a length of 217 cm of wire, find the e.m.f. of the cell. When the cell is shunted by a resistance of 15 2 the balancing length is reduced to 200 cm. Find the internal resistance of the cell.

A potentiometer wire of length 4 m has a resistance of 8 Q2. It is connected in series with a battery of e.m.f 2 volts and negligible internal resistance. If the e.m.f of a cell balances against a length of 217 cm of wire, find the e.m.f. of the cell. When the cell is shunted by a resistance of 15 2 the balancing length is reduced to 200 cm. Find the internal resistance of the cell.