The work function of Cs is 2.14eV.Find
(a) threshold frequency for Cs
(b) Wavelength of incident light if the photo current is brought to zero by stopping potential of 0.6 V.

Explanation

Wave function
`omega = 2.14eV`
(a) Threshold frequency `omega = hnu_(0)`
`nu_(0) = (omega)/(h) = (2.14 xx 1.6 xx 10^(-19))/(6.62 xx 10^(-34))`
`=5.174 xx 10^(14)H_(2)`
(b) `"As "k_(max) = eV_(0)= 0.6eV`
= 2.74eV
Wave length of photon `lambda = (hc)/(E) = (6.62 xx 10^(-34) xx 3 xx 10^(-8))/(2.74 xx 1.5 xx 10^(-19))`
`=4530 Å`