In Fig. what should be the speed of the charged particle so that it cannot collide with the upper wall? Also, find the coordinates of the point where the particle strikes the lower plate in the limiting case of velocity.

Explanation

(i) The path of the particle will be circular larger the velocity, larger will be the radius. For particle not to s strike `R < d`
`therefore (mv)/(qB)ltd`
`impliesvlt(qBd)/(m)`

(ii) for limiting case `v=(qBd)/(m)`
`R=d`
`therefore` coordinate = `(-2d,0,0)`