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. 1.0 mm
C. 1.2 mm
D. 1.5 mm

Answer

C

Explanation

`(beta_(1))/(beta_(2))=(lamda_(1))/(lamda_(2)) or (1.0)/(beta_(2))=(5000)/(6000)`
or `beta_(2)=(6000)/(5000)=1.2 mm`.