The wavelength of light in the visible region is about 390 nm for violet colour and about 760 nm for red colour. The energy of photon in eV at violet end is

Options

A. 2.32
B. 3.19
C. 1.42
D. 4.13

Answer

B

Explanation

(b) : Energy of the incident photon, `E=hv=(hc)/(lamda)` For violet light, `lamda=390nm`
`:."Incident photon energy,"=(6.63xx10^(-34)xx3xx10^(8))/(390xx10^(-9))J`
`=5.1xx10^(-19)J=(5.1xx10^(-19))/(1.6xx10^(-19))eV=3.19eV`