A particle of mass m and charge q is accelerated by a potential difference V volt and made to enter a magnetic field region at an angle `theta` with the field. At the same moment, another particle of same mass and charge is projected in the direction of the field from the same point. Magnetic field induction is B. What would be the speed of second particle so that both particles meet again and again after regular interval of time. Also, find the time interval after which they meet and the distance travelled by the second particle during that interval.

Explanation

`qV=1/2mv_1^2 implies v_1 =sqrt((2qV)/m)`
To meet them again and again:
`v_2=v_1cos theta=sqrt((2qV)/m) cos theta`

Time interval : `T=(2pim)/(qB)`
Distance after which they meet=1pitch=`v_2T`
`=sqrt((2qV)/m)cos thetaxx(2pim)/(qB)=pisqrt((8Vm)/(qB^2))cos theta`