Q.1
In an experiment to measure the internal resistance of a cell by a potentiometer, it is found that the balance point is at a length of 2 m, when the cell is shunted by a 5W resistance and at a length of 3 m, when the cell is shunted by a 10 W resistance. The internal resistance of the cell is
(a) 1.5 W (b) 10 W (c) 15 W (d) 1 W
Ans : (b)
Q.2
A resistance of 4W and a wire of length 5 metres and resistance 5W are joined in series and connected to a cell of e.m.f. 10V and internal resistance 1W. A parallel combination of two identical cells is balanced across 300 cm of the wire. The e.m.f. of each cell is
(a) 1.5 V
(b) 3.0 V
(c) 0.67 V
(d) 1.33 V
Ans. (b)