Ligth of waveelength `2,200 overset @A` falls on a metal with work function 4.1 eV.Find teh maximum kinetic energy of th emitted elecrtrons and the stopping potential.Gien that `h=6.62 xx 10^(-34) J s,c= 3 xxx 10^8 m s^9-1) ` and `e= 1.6 xx 10^(-19) C.`

Explanation

`lambda = 2200 Å = 2200 xx 10^(-10) m`
`lambda = 22 xx 10^(-8) m`
Work function = `phi_0 = 4.1 eV`
Maximum kinetic energy = `K.E._("max") = ? `
`E = (6.62 xx 10^(-34) xx 3 xx 10^8)/(22 xx 10^(-8))`
`= (19.86)/2 xx 10^(-34 + 8 + 8)`
`E = 0.903 xx 10^(-18)`
`= 9.03 xx 10^(-19) J`
`(9.03 xx 10^(-19))/(1.6 xx 10^(-19)) eV`
`E = 5.64 eV`
`K.E._("maxi") = E = phi_0`
`= 5.64 - 4.10`
`= 1.54 eV`
But `eV_s = K.E._("maxi")`
`eV_s = 1.54 eV`
`implies V_s = 1.54 ` volt.