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

Hint:

In a moving coil galvanometer, deflection is proportional to the current passing through the coil.

Answer 1

The Correct Option is B

In analyzing the given assertion and reason, we need to establish their validity and relationship.

The assertion (A) states: "The deflection in a galvanometer is directly proportional to the current passing through it." This assertion is true. A galvanometer works on the principle that when an electric current passes through a coil in a magnetic field, it experiences a magnetic torque that causes it to rotate. The amount of deflection is directly related to the current flowing through it.

The reason (R) states: "The coil of a galvanometer is suspended in a uniform radial magnetic field." This reason is also true. The galvanometer's design ensures that the coil is in a uniform radial magnetic field, which maintains consistent sensitivity across the rotation of the coil.

While both the assertion and the reason are correct statements, the reason given is a part of the design characteristic of the galvanometer, ensuring uniform sensitivity. However, it does not directly explain why the deflection is proportional to the current. Instead, the proportionality of deflection to current is primarily because of the magnetic torque proportional to the current in the coil. Therefore, the correct option is:

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