In a certain double slit experimental arrangement interference fringes of width `1.0mm` each are observed when light of wavelength `5000Å` is used. Keeping the set up unaltered, if the source is replaced by another source of wavelength `6000Å`, the fringe width will be

Options

A. (a) `0.5mm`
B. (b) `1.0mm`
C. (c) `1.2mm`
D. (d) `1.5mm`

Answer

C

Explanation

`beta_1/beta_2=lambda_1/lambda_2` or `(1.0)/(beta_2)=(5000)/(6000)` or `beta_2=(6000)/(5000)=1.2mm`.