Bichromatic light of wavelengths `lambda_1= 5000Å and lambda_2=7000Å` are used in YDSE. Then,

Options

A. 14th order maxima of `lambda_1` will coincide with 10th order maxima of `lambda_2`
B. 21st order maxima of `lambda_2` will coincide with 15th order maxima of `lambda_1
C. 11th order minima of `lambda_1 will coincide with 8th order minima of `lambda_2`
D. 3rd order minima of `lambda_1` will coincide with 4th order minima of `lambda_2`

Answer

A, C

Explanation

For overlapping of maxima
`(n_1lambda_1D)/d = (n_2lambda_2D)/d`
or ` n_1/n_2 = lambda_2/lambda_1=7/5,14/10…………`
` rArr` 14th order maxima of `lambda_1` will coincide with
10th order maxima of `lambda_2`.
For overlapping of minima
` ((2n_1 -1)lambda_1D)/(2d) = ((2n_2-1)lambda_2D)/(2d)`
` :. ((2n_1-1)/(2n_2-1)) = lambda_2/lambda_1 = 7/5`
(c)Option with `n_1 = 11` and `n_2 = 8` gives this ratio.