A flat dielectric disc disc of radius R carries an excess charge on its surface. The surface charge density is sigma. The disc rotates about an axis perpendicular to its plane passing through the center with angular velocity omega. Find the magnitude of the torque on the disc if it is placed in a uniform magnetic field whose strength is B which is directed perpendicular to the axis of rotation

A flat dielectric disc disc of radius R carries an excess charge on it

1.	A flat dielectric disc disc of radius R carries an excess charge on its surface. The surface charge density is sigma. The disc rotates about an axis perpendicular to its plane passing through the center with angular velocity omega. Find the magnitude of the torque on the disc if it is placed in a uniform magnetic field whose strength is B which is directed perpendicular to the axis of rotation
Answer» `(1)/(4) sigma omega PI ` B R `(1)/(4) sigma omega pi B R^(2)` `(1)/(4) sigma omega pi B R^(3)` `(1)/(4) sigma omega pi B R^(4)` ANSWER :A::B::D

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