Work function of metal a,b and c are 1.92 eV 2.0 eV and 5 eV respectively .According to Einstein's equation radiation 4100 Å will produce electron emission which metal or metals?

Options

A. None of these
B. Only A
C. Only (A) and (B)
D. All (A),(B),(C )

Answer

C

Explanation

`E=(hc)/(lambda)=(hc)/(elambda(in Å ))eV=(6.6xx10^(-34)xx3xx10^(8))/(1.6xx10^(-19)xxlambda (in Å))`
`implies E=(12375)/(lambda (In Å))eVimpliesE=(12375)/(4100)eV`
`impliesE~~3 eV`
If work function of metal is less than 3 eV than from radiation of 4100 Å photon electric emission will take place so here in metal a and b phototelectric emission will take place.