Practice portal › Current Electricity › Wheatstone Bridge, Metre Bridge and Potentiometer

In the given figure of meter 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. [Figure: a 5 V cell across the ends of wire AB; R₁ and R₂ in series between the same two ends; galvanometer from the R₁-R₂ junction to jockey C on AB.]

Asked in JEE Main 27th July 2nd Shift 2022 · Metre bridge

Figure: Metre bridge
Answer: 40

Step-by-step solution

At balance (R₁)/(R₂)=(R_AC)/(R_CB)=l/(100-l) for a uniform wire.

Doubling the radius scales every part of the wire's resistance by the same factor 1/4.

The ratio, and so the balance point, is unchanged: l=40 cm.

More Wheatstone Bridge, Metre Bridge and Potentiometer questionsAll Wheatstone Bridge, Metre Bridge and Potentiometer questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer