Question

Statement I If we increase the current sensitivity of a galvanometer by increasing number of turns, its voltage sensitivity also increases.
Statement II Resistance of a wire is directly proportional to its length.

• A. Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I.
• B. Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I.
• C. Statement I is correct but Statement II is incorrect.
• D. Statement I is incorrect but Statement II is correct.

Answer 1

Answer: (D)

Current sensitivity, $S_{i}=\frac{N B A}{k}$
and voltage sensitivity, $S_{V}=\frac{N B A}{k R}$
So, when $S_{i}$ is increased by increasing number of turns $N$, length of wire used also increases and so, $R$ increases.
Hence, $S_{V}$ may remain same or decrease whereas $S_{i}$ increases.