A charged particle enters a unifrom magnetic field with velocity vector at an angle of `45^(@)` with the magnetic field . The pitch of the helical path followed by the particles is `rho` . The radius of the helix will be

Options

A. `P/(sqrt(2)pi)`
B. `sqrt(2)P`
C. `P/(2pi)`
D. `(sqrt(2)P)/(pi)`

Answer

C

Explanation

`(mvsintheta)/(qB)` & `P=(2pim vcostheta)/(qB)`
`:.r/P=(tantheta)/(2pi)=1/(2pi)`
`r=P/(2pi)`