A gas absorbs a photon fo ` 355nm` and emits at two wavelengths . If one fo the emission is at ` 6 80` nm , the other si at :

Options

A. ` n= 4 , l=1`
B. ` n = 4, l=0`
C. ` n = 3, 1=2`
D. `n= 3, l=1`

Answer

C

Explanation

` E = hv = hc //lambda `
` E =E_1 + E_2` or `( hc)/(lambda ) = (hc)/(lambda _1) + (hc)/(lambda _2)`
` rArr lambda = 1/lambda = 1/(lambda _1) +1/(lambda _2) rArr 1/( 355) = 1/(680) + 1/(lambda _2)`
`:. lambda _2 = ( 355 xx 680)/( 680 -355) = 742.769 nm ~~ 743 nm`.