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. `0.5 mm`
B. 1 mm
C. `1.2 mm`
D. `1.5 mm`

Answer

C

Explanation

`(beta_(2))/(beta_(1))=(lambda_(2))/(lambda_(1))`
`:. beta_(2)=(lambda_(2))/(lambda_(1)) beta_(1)=(6000xx1)/(5000)=1.2 mm`