Question

In the given figure of meter of bridge experiment, the balancing length AC corresponding to null deflection of the galvanometer is 40 cm. The balancing length, if the radius of the wire AB is doubled, will be _______ cm.

Fig.

Answer 1

The correct answer is 40
Even if the radius of wire is doubled, the balancing point would not change as
$\frac{x}{l-x} = \frac{R_1}{R_2}$
, which is not including a term of area.
Therefore , balancing length will be 40 cm