Question

Calculate fringe width on a screen 1 m from the slits if light of 600 nm is used and the separations of the two image slits in the two positions are 0.2 mm and 7.2 mm respectively .

• A. 0.5 mm
• B. 0. 5 cm
• C. 0.5 m
• D. 0.05 mm

Answer 1

Answer: (A)

0.5 mm

$d=\sqrt{d_1{d}_2}=1.2mm$

Hence fringe width= $\frac{D\lambda }{d}$

$=\frac{1\times 600\times {10}^{-9}}{1.2\times {10}^{-3}}$

$=0.5mm$