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Question
- Assertion (A): The deflecting torque acting on a current-carrying loop is zero when its plane is perpendicular to the direction of the magnetic field.
- Reason (R): The deflecting torque acting on a loop of the magnetic moment `vecm` in a magnetic field `vecB` is given by the dot product of `vecm` and `vecB`.
Options
Both Assertion (A) and Reason (R) are true and (R) is the correct explanation of (A).
Both Assertion (A) and Reason (R) are true and (R) is not the correct explanation of (A).
Assertion (A) is true and Reason (R) is false.
Assertion (A) is false and Reason (R) is also false.
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Solution
Assertion (A) is true and Reason (R) is false.
Explanation:
The deflecting torque acting on a current-carrying loop placed in a magnetic field is given by the equation:
`vectau = vecm xx vecB`
Where τ is the deflecting torque, m is the magnetic moment of the loop, and B is the magnetic field. The symbol "x" denotes the vector product.
When the plane of the loop is perpendicular to the direction of the magnetic field, the angle between the magnetic moment vector and the magnetic field vector is 90°.
Both the deflecting torque and the vector product of the two vectors attain their maximum levels in this condition. However, the dot product of the two vectors is zero.
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