A magnetic needle lying parallel to a magnetic field requires W units of work to turn it through 60°. The torque needed to maintain the needle in this position will be
(A) Ö3 W (B) W
(C) (Ö3/2) W (D) 2W
2 comments:
I think
b) w
w=F dot s
torque=r cross F
Now try to solve the problem.
The answer is (A)
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