A uniform field is exists in the region directed away from the page. A charged particle, moving in the plane of the page follows a anticlockwise spiral of increasing radius as shown. True explanation is:

Options

A. the charge is positive and slowing down
B. the charge is negative and slowing down
C. the charge is positive and speeding up
D. the charge is negative and speeding up

Answer

A

Explanation

`R=(mv)/(qB)` : `vec(F) = q(vec(v)xxvec(B))`