A particle with charge q and mass m is shot with K.E ''k'' into the region between two plates.If magnetic field between plates is B.How large B must be if the particle is to miss collision with the opposite plate?

Ans)To just miss the collision of the opposite plate,the paticle must move in a circular path of radius ''d'' so that,

Bqd=mv²/d

Bqd=mv------(1)

but K=1/2 mv²

K=(mv)² /m2

2mK=(mv)²

mv=(2Km)^1/2 ---------------(2)

substitutng (2) in (1)

Bqd=(2Km)^1/2

B=(2Km)^1/2/qd