Two monochromatic sources of light A and B of wavelengths 5500 Å and 4400 Å respectively are used simultanesouly to produce interference bands on a screen. Which orders of the fringes in the two interference patterns will coincide?

Options

A. `5^(th)` order of A and 3rd order of B
B. 10th order of A and 8th order of B
C. 8th order of A and 10th order of B
D. 4th order of A and 6th order of B

Answer

C

Explanation

`lamda_(1) gt lamda_(2) " "therefore n_(2) gt n_(1)`
`n_(1)lamda_(1) =n_(2)lamda_(2)`
`therefore 5500(n-2)=4400(n)" "therefore 5n-10=4n" "therefore n=10`
`therefore`8th order of A and 10th order of B.