A potential barrier of `0.3V` exists across a `p-n` junction.
(a) if the depletion region is `1mum` width. What is the intensity of elctric field in this region ?
(b) An electron with speed `5xx10^(5)m//sec` approaches this `p-n` junction from `n`-side, what will be its speed on entering the `p`-side?

Explanation

(a) `E=(V)/(d)=(0.3)/(1xx10^(-6))=3xx10^(5)V//m`
(b) Retardation of electron `a=(eE)/(m)`
`v^(2)=u^(2)-2as`
`=(5xx10^(5))^(2)-(2xx1.6xx10^(-19)xx3xx10^(5))/(9.1xx10^(-31))xx10^(-6)`
`=14.3xx10^(10)`
`v=3.8xx10^(5)m//sec`