AIPMT MAINS2012Physics-Magnetic Effects of Current and Magnetism
AIPMT MAINS 2012 Physics Torque on a Magnetic Dipole MCQ Question
Type: MCQ-conceptual-Medium-Class 12
A magnetic needle suspended parallel to a magnetic field requires √3 J of work to turn it through 60°. The torque needed to maintain the needle in this position will be:
A
2√3J
B
3J
C
√3J
D
3/2 J
Correct Answer
Option B
Detailed Explanation
The work done is given by W = MB(cos⁰⁻ cos 60°) = MB/2 = √3J. The torque τ = MB sin 60° = MB√3/2. Solving these equations gives τ = 3J.
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