Question

Photon having wavelength `12.4nm` was allowed to strike a metal plate having work function `25eV`.Calculate the-
(a) Maximum kinetic energy of photoelectrons emitted in eV.
(b) Wavelength of electron with maximum kinetic energy in `A^(@)`.
(c ) Calculate the uncertainity in wavelength of emitted electron, if the uncertainity in the momentum is `6.62xx10^(20)kg m//sec`

Answer 1

Correct Answer - (a) `75eV;` (b)`1.414 Å;` (c) `2xx10^(-14)m`
(a) `KE=(hc)/(lambdae)-Phi_(0)=100-25=75`
(b)` lambda=(h)/sqrt(2m.KE)`=`(6.63xx10^(-74))/(sqrt(2xx9.1xx10^(-31)xx75xx1.6xx10^(-19))`
`=1.414xx10^(-10)m`
`DeltaXge(h)/(4pi)`
`DeltaXge(h)/(4piXXDeltaP)`=`2xx10^(-14)m`