Wave Optics - Result Question 18

18. In Young’s double slit experiment carried out with light of wavelength $(\lambda)=5000 \AA$, the distance between the slits is $0.2 mm$ and the screen is at $200 cm$ from the slits. The central maximum is at $x=0$. The third maximum (taking the central maximum as zeroth maximum) will be at $x$ equal to

[1992]

(a) $1.67 cm$

(b) $1.5 cm$

(c) $0.5 cm$

(d) $5.0 cm$

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Answer:

Correct Answer: 18. (b)

Solution:

  1. (b) $x=(n) \lambda \frac{D}{d}=3 \times 5000 \times 10^{-10} \times \frac{2}{0.2 \times 10^{-3}}$

$ =1.5 \times 10^{-2} m=1.5 cm $