Question

The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil. Soft iron has high magnetic permeability and cannot be easily magnetized or demagnetized.

• A. If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
• B. If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
• C. If Assertion is correct but Reason is incorrect
• D. If both the Assertion and Reason are incorrect

Answer 1

Answer: (C)

If Assertion is correct but Reason is incorrect

Answer 2

Sensitivity of galvanometer, $s = \frac{\theta}{i} \simeq \frac{\tan \theta}{i} = \frac{\mu_0 N}{2 R B_H}$ If a magnetic material is placed inside coil of galvanometer, then $s' = \frac{\mu_r \mu_0 N}{2RB_H}$