The resistance of the meter bridge AB is given figure is 4. With a cell of emf ε=0.5 V and rheostat resistance R_h= 2 the null point is obtained at some point J. When the cell is replaced by another one of emf ε= the same null point J is found for R_h=6 . The emf is ;

(a)

0.6 V

(b)

0.5 V

(c)

0.3 V

(d)

0.4 V

Question

Question ID - 50312 :-

The resistance of the meter bridge AB is given figure is 4. With a cell of emf ε=0.5 V and rheostat resistance R_h= 2 the null point is obtained at some point J. When the cell is replaced by another one of emf ε= the same null point J is found for R_h=6 . The emf is ;

(a)

0.6 V

(b)

0.5 V

(c)

0.3 V

(d)

0.4 V

1 Answer

5876 Votes

score 3537 · Accepted Answer

Answer Key : (c) -

Potential gradient with R_h =2 is ×=L=100cm

Let null point be at cm

Thus =0.5V=……(1)

Now with R_h = 6

and at null point

…...(2)

Dividing equation (1) by (2) we get

thus