Question

Assertion (A): The deflection in a galvanometer is directly proportional to the current passing through it.
Reason (R): The coil of a galvanometer is suspended in a uniform radial magnetic field.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false and Reason (R) is also false.

Hint:

The deflection in a galvanometer is directly related to the current, but the suspension of the coil in a uniform magnetic field is not the only reason for this relationship.

Answer 1

The Correct Option is B

To solve this assertion-reason type question, we need to evaluate the truth of each statement and their relationship to each other.

Assertion (A): The deflection in a galvanometer is directly proportional to the current passing through it.
The assertion states a fundamental principle of how galvanometers work. When a current passes through the coil of a galvanometer, it experiences a torque due to the magnetic field, causing a deflection which is generally proportional to the current.
Therefore, the assertion is true.

Reason (R): The coil of a galvanometer is suspended in a uniform radial magnetic field.
The reason describes the specific construction of a galvanometer where the coil is placed in a uniform radial magnetic field. This design ensures that the torque experienced by the coil is proportional to the current, regardless of its position, as the angle between the plane of the coil and magnetic field is always constant.
Hence, the reason is also true.

While the reason correctly describes an aspect of the galvanometer's design, it is not the direct explanation for why the deflection is proportional to the current. The deflection being proportional to the current is a result of the linear relationship between current, magnetic field, and torque, not merely due to the coil being in a radial field.

Therefore, the correct conclusion is: Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).