Wavelength of ultraviolet light is `3 xx 10^(-5) cm`. What will be the energy of a photon of this light, in eV? `(c = 3 xx 10^(10) m.s^(-1))`

Explanation

Planck's constant, `h = 6.625 xx 10^(-27)` erg.s
Wavelength, `lamda = 3 xx 10^(-5) cm`
`:.` Energy of a photon
`E = (hc)/(lamda) = ((6.625 xx 10^(-27)) xx (3 xx 10^(10)))/(3 xx 10^(-5))` erg
`= ((6.625 xx 10^(-27)) xx (3 xx 10^(10)))/((3 xx 10^(-5)) xx (1.6 xx 10^(12)))eV`
= 4.14eV