The work function of a photosensitive element is 2ev. Calualate the velocity of a photoelectron when the element is exposed to a light of wavelength `4xx10^(3) overset(0)A`.

Explanation

Einstein,s photoelectric equation is `1/2mv^(2)=(hc)/lambda-W_(0)`
`1/2mv^(2)=(6.63xx3)/(4xx10^(3)xx10^(-10)) xx 10^(-26)-2xx1.6xx10^(-19)`
`v^(2)=(1.765xx2)/9.1xx10^(12)`
`v=sqrt((1.765xx2)/(9.1))xx10^(6)=6.228xx10^(5)ms^(-1)`