A charged particle is projected in a magnetic field `vec(B)=10hat(k)T` from the origin in `x-y` plane. The particle moves in a circle and just touches a straight line `y=5(m)` at `x=5sqrt(3)(m)`. Then ( mass of particle `=5xx10^(5-)kg`, charge `=1 mu C )`

Options

A. the particle is projected at an angle `60^(@)` with `x-` axis
B. the radius of curvature at `(5 sqrt(3),5)` is `10m`
C. the speed of the particle is `2m//s`
D. the particle moves in a helical path.

Answer

A,C

Explanation

`r=(mv sintheta)/(qB)=5xx10^(-5)`
`x=5sqrt(3)" "y_(x)=tan(180^(@)-theta)`