What is the wavelength of the radiation with photon energy which is the mean value of photon energies of radiations with wavelength `lamda_1 = 4000 Å` and `lamda_2 = 6000 Å` ?

Options

A. `5000 Å`
B. `5200 Å`
C. `5600 Å`
D. `4800 Å`

Answer

D

Explanation

(d) `(hc)/(lamda_3) = ((hc)/(lamda_1) + (hc)/(lamda_2))/(2)`
`rArr (1)/(lamda_3) = (1)/(2) ((1)/(lamda_1) + (1)/(lamda_2))`
=`(1)/(2) ((1)/(4000) +(1)/(6000))`
`rArr lamda_3 = 4800 Å`.