A photon of wavelength `4 xx 10 ^(-7) m` strickes on metal surface, the work function of the metal being `2.13` eV. Calculate
energy of the photon (eV)

Explanation

We are given that
Wavelength of phton ` 4 xx 10 ^(-7) m`
Work function of metal `= 2.13 eV`
We know that , `E = ( hc)/( lamda ) = ( 6.62 xx 10 ^(-34) xx 3 xx 10 ^(8))/( 4 xx 10 ^(-7) m ) = 4.97 xx 10 ^(-19) J`
Also, `1 eV = 1. 6 xx 10 ^(-19) J`
`or, 1. 6 xx 10 ^(-19) J = 1 e V`
`1 J = ( 1)/( 1. 6 xx 10 ^(-19))`
`4.97 xx 10 ^(-19) =(1)/( 1. 6 xx 10 ^(-19) ) xx 4. 97 xx 10 ^(-19) = 3. 19 eV.`