Question

Assertion-Reason Type Question Assertion (A): Torque acting on a current loop in a magnetic field is maximum when the plane of the loop is parallel to the magnetic field.
Reason (R): Torque on a magnetic dipole is given by: \[ \tau = MB\sin\theta \] where \(\theta\) is the angle between magnetic moment and magnetic field. Choose the correct answer from the options given below:

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

Hint:

Remember: \[ \tau_{\max}=MB \] Maximum torque occurs when magnetic moment is perpendicular to magnetic field.

Answer 1

The Correct Option is A

Step 1: Recall torque formula. Torque on a magnetic dipole in a magnetic field is given by: \[ \tau = MB\sin\theta \] Torque is maximum when: \[ \sin\theta = 1 \] Thus: \[ \theta=90^\circ \]

Step 2: Relate angle with loop orientation. Magnetic moment is perpendicular to plane of loop. If magnetic moment is perpendicular to field: \[ \theta=90^\circ \] then plane of loop becomes parallel to magnetic field. Thus Assertion is true. Reason is also true and correctly explains Assertion. Therefore: \[ \boxed{\text{ Both Assertion and Reason are true and Reason is the correct explanation of Assertion.}} \]