Charge is sprayed onto a large non conducting belt above the left hand roller. The belt carries charge with a uniform surface charge density delta, as it moves with a speed v between the rollers as shown. The charge is removed by a wiper at right hand roller. For a point just above the sheet mark the correct option.

Options

A. magnetic field is `(mu_(0)sigmav)/2` , out of the plane of the page, parallel to axis of roller.
B. magnetic field is `mu_(0)sigma` , out of the plane of the page perpendicular to axis
C. electric field is `(varepsilon_(0)sigma)/2` perpendicular to the plane of sheet
D. If an electron moves parallel to V just above the sheet it will experience an upward magnetic force.

Answer

A, D

Explanation

(A) `(mu_(0)K)/2 hence K=deltaV`
(D) `F=qvec(u)xxvec(B)` hence upwards.