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

Explanation

`lambda=488nm =488xx10^(-9)m, upsilon_(0)=0.38V`
`h upsilon=phi_(0)+(1)/(2)mv_("max")^(2), h (c )/(lambda)=phi_(0)+eV_(0)`
`phi_(0)=h (c )/(lambda)-eV_(0)=(6.6xx10^(-34)xx3xx10^(8))/(488xx10^(-9))-1.6xx10^(-19)xx0.38=3.46xx10^(-19)J=2.16eV`