Question

When two resistances x and y are put in the left hand and right hand gaps in a meter bridge, the null point is at 60 cm. If x is shunted by a resistance equal to half of itself then find the shift in the null point?

Answer 1

Answer:

Null point shifts 15 cm to the right.

Explanation:

x=yx(L 2/L 1)

x=yx(40/60)......1

(x/2)=yx(L 2/L 1)

x=2xyx(L 2/L 1)......2

equation 1=equation 2

2xyx(L 2/L 1) = yx(40/60)

L 2/L 1 = 40/120=1/3

L 1=3 x L 2

Then L 1=25 cm

new null position is at 75 cm

The shift in null position is by 15 cm to the right.