Two large metal sheets carry surface currents as shown in figure . The current through a strip of width dl is Kdl where K is a constant . Find the magnetic field at the points P,Q and R. `

Explanation

(a) `B = (1)/(2) mu_(0)K` (as proved in Chapter 5)
(b)
Since `v` is `_|_^(ar)` to `B`, a particle moves in a circle of radius
`R = (mv)/(Bq) = (2m v)/(mu_(0) K q)`
If the particle does not hit the plate
`R le d`
`(2 m v)/(mu_(0) K q) le q`
`v le (mu_(0) K q d)/(2m)`
`v_(max) = (mu_(0) K d q)/(2m)`
( c) `v_|_B`, path will be circle
`r = (m v)/(Bq) = (m v)/(mu_(0) K q)`
`v = (mu_(0) K q r)/(m)`