Optics 6 Question 16
18. Young’s double slit experiment is carried out by using green, red and blue light, one colour at a time. The fringe widths recorded are $\beta _G, \beta _R$ and $\beta _B$ respectively.
Then,
(a) $\beta _G>\beta _B>\beta _R$
(b) $\beta _B>\beta _G>\beta _R$
(c) $\beta _R>\beta _B>\beta _G$
(d) $\beta _R>\beta _G>\beta _B$
(2012)
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Solution:
- Fringe width $\beta=\frac{\lambda D}{d}$ or $\beta \propto \lambda$
Now, $\lambda _R>\lambda _G>\lambda _B$
$$ \therefore \quad \beta _R>\beta _G>\beta _B $$
