A charged particle of mass m and charge q, a uniform magneric field B acting into the plane. The plane is frictional having coefficient of friction `mu`. The speed of charged particle just before entering into the region is `V_(0)`. The radius of curvature of the path after the time `(v_(0))/(2mug)` is

Options

A. `(mv_(0))/(qB)`
B. `(mv_(0))/(2qB)`
C. `(mv_(0))/(4qB)`
D. None of these

Answer

b

Explanation

Here, centripetal acceleration is provided by magnetic force but tangential acceleration is provided by force of friction
`(mv^(2))/r=qvB`
`:. r=(mv)/(qB)`
Tangential acceleration `=a=(-mumg)/m`
`v=-mug((v_(0))/(2mug)) =(v_(0))/2`
`:. r=(mv)/(qB)=(mv_(0))/(2qB)`