Define threshold frequency.

Photo-electric emission is observed from a metalli surface for frequenceis f_(1) and f_(2) of the incident light. (f_(1)gtf_(2)) .If the maximum values of K.E. of photo-electrons emitted in two cases are in the ratio 1:n, then the threshold frequency of a metallic surface is .......

Frequency of radiation incident on metal surface is called threshold frequency.

Value of threshold frequency depend on which factors?

Explain -"for photoelectric emission frequency of incident radiation should be greater than threshold frequency".

Given in fig. is the graph between frequency v of the incident light and maximum kinetic energy (E_(k)) of the emitted photoelectrons. Find the values of (i) threshold frequency and (ii) work function form the graph.

Energy corresponding to threshold frequency of metal is 6.2 eV.For given radiation stopping potential is 5 V then incident radiation will be in …region.

Work function of potassium is 2.30 eV.Find (a)threshold frequency of potassium (b)the wavelength of the incident light if the photocurrent is brought to zero by a stopping potential of 0.60 V

Light of frequency 7.21xx10^(14) Hz is incident on a metal surface .Electrons with a maximum speed of 6.0xx10^(5)m//s are ejected from the surface .What is the threshold frequency for photoemission of electrons?