Distance of 5th dark fringe from centre is 4 mm. If D = 2 m, λ = 600 nm, then distance between slits is :

Question

Distance of 5th dark fringe from centre is 4 mm. If D = 2 m, λ = 600 nm, then distance between slits is : (A) 1.35 mm (B) 2.00 mm (C) 3.25 mm (D) 10.35 mm

Tardigrade Admin · Accepted Answer

Distance of 5th dark Fringe from centre = (9β/2) (9×λ× D/2× d)=4×10-3 ⇒ d=(9×6×10-7×2/2×4×10-3)=1.35 mm

Q. Distance of 5^th dark fringe from centre is 4 mm. If D = 2 m, $λ$ = 600 nm, then distance between slits is :

1.35 mm

2.00 mm

3.25 mm

10.35 mm

Distance of 5^th dark
Fringe from centre = $\frac{9 β}{2}$
$\frac{9 \times λ \times D}{2 \times d} = 4 \times 1 0^{- 3} \Rightarrow d = \frac{9 \times 6 \times 1 0 ^{- 7} \times 2}{2 \times 4 \times 1 0 ^{- 3}} = 1.35$ mm

Q. Distance of 5th dark fringe from centre is 4 mm. If D = 2 m, λ = 600 nm, then distance between slits is :