Magnetic field due to currentHard
Question
A thin non conducting disc of radius R is rotating clockwise (see figure) with an angular velocity w about its central axis, which is perpendicular to its plane. Both its surfaces carry + ve charges of uniform surface density. Half the disc is in a region of a uniform, unidirectional magnetic field B parallel to the plane of the disc, as shown. Then,
Options
A.The net torque on the disc is zero
B.The net torque vector on the disc is directed leftwards
C.The net torque vector on the disc is directed rightwards
D.The net torque vector on the disc is parallel to B
Solution
= 
(- 
) × B (- ĵ) = 
(- î) (Letfward)Create a free account to view solution
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