White light of wavelength in range 400 nm to 700 nm is incident normaly on a young's double slit experiment apparatus. The distance betweenn slits is `d=1` mm and distance between plane of the slits and screen in 0.8 m. At a point on the screen just in front of one of the slits the missing wavelength is (are)

Options

A. 533.3 nm
B. 416.7 nm
C. 666.7 nm
D. 577.7 nm

Answer

B

Explanation

For min `dsintheta=(n-(1)/(2))lamda`
`(dy)/(D)=(2n-1)(lamda)/(2)` `y=0.5xx10^(-3)`
`y=(2n-1)(Dlamda)/(2d)` `d=1xx10^(-3)`
`d=0.8m`
`lamda=(1250)/((2n-1))cm`
`n=1` ,`lamda_(1)=416.7nm`
`n=2` , `lamda_(2)=178.57nm`