Light of wavelength 488 nm is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the cathode, the stopping (cut-off) potential of photo electrons is 0.38 V. Find the work function of the material from which the cathode is made.

Explanation

Frequency of incidental light,
`f = (c)/(lamda) = (3 xx 10^(8))/(488 xx 10^(-9)) = 6.15 xx 10^(14)Hz`
`:.` Work function,
`W_(0) = hf - eV_(0)`
`= 6.626 xx 10^(-34) xx 6.15 xx 10^(4) - 1.6 xx 10^(-19) xx 0.38`
`= 3.467 xx 10^(-19)J = 2.167 eV`