Light of 2200 Å falls on a metal surface. The work function is given to be 4.1 eV for the metal. Find the maximum kinetic energy of the emitted electrons and the stopping potential.
Given `h = 6.6 xx 10^(-34) Js, c = 3 xx 108 ms^(-1), e = 1.6 xx 10_(-19)C`.

Explanation

`lambda=2200 dotA=2200 xx 10^-10 m`
`lambda=22 xx 10^(-8)m`
`phi_(0)=4.1 eV`
`K.M_("maxi")=?`
`E=(hc)/lambda`
`E=(6.62 xx 10^-34 xx 3 xx 10^8)/(22 xx 10^-8)`
`=19.86/22 xx 10^(-34+8+8)`
`E=0.902 xx 10^-18`
`=9.02 xx 10^(-19)J`
`=(9.02 xx 10^(-19))/(1.6 xx 10^(-19))eV`
`E=5.63 eV`
`K.E_((max))=E=phi_(0)`
`(K.E)_(max)=5.63-4.10`
`(K.E)_max=1.53 eV`
`eV_(0)=K.E_(max)`
`eV_(0)=1.54 eV`
`V_(0)=1.54 "volt"`.