APSC Legal Metrology: Paper 2 MCQ on Wheatstone bridge

A Wheatstone bridge is in balanced condition, when the
(A) current through the galvanometer is maximum
(B) voltage across the galvanometer is maximum
(C) current supplied by the source is zero
(D) voltage across the galvanometer is zero

The correct answer is:
(D) voltage across the galvanometer is zero

Explanation:

A Wheatstone bridge is said to be in a balanced condition when the ratio of the two resistances in one leg is equal to the ratio in the other leg. Under this condition:

• No current flows through the galvanometer, because the potential difference (voltage) across it is zero.
• This is the defining condition for balance in a Wheatstone bridge.

So, option D is correct.