An infinitely long current carrying wire carries current i. A charge of mass m and charge q is projected with speed v parallel to the direction of current at a diatance r from it. Then, the radius of curvature at the point of projection is

Options

A. `(2rmv)/(qmu_0i)`
B. `(2pirmv)/(qmu_0i)`
C. r
D. cannot be determined

Answer

B

Explanation

`F=qvB=(qvmu_0i)/(2pir)`
`(mv^2)/R=(qvmu_0i)/(2pir)implies R=(2pirmv)/(qmu_0i)`