The work function of a metal is `4.2 eV` , its threshold wavelength will be

The work function of Na metal is 2.3 eV , then the threshold wavelength lies in the following region of EM spectrum -

The work function of a metal is 3eV. Calculate its threshold wavelength.

If the work function of a photo - metal is 6.825 eV . Its threshold wavelength will be ( c = 3 xx 10^(8) m//s)

The work function of photometal is 6.626 eV. What is the threshold wavelength ?