Question

In a metre bridge experiment, null point is obtained at 20 cm from one end of the wire when resistance X is balanced against another resistance Y. If X < Y, then where will be the new position of the null point from the same end, if one decides to balance a resistance of 4X against Y?

• A. 50 cm
• B. 80 cm
• C. 40 cm
• D. 70 cm

Answer 1

The correct option is A 50 cm

$\frac{X}{Y}=\frac{20}{100-l}=\frac{20}{80}=\frac{1}{4}Y=4X\frac{4X}{Y}=\frac{l^{\prime }}{100-l^{\prime }};l^{\prime }=50cm$