Optics Ques 33
- A transparent slab of thickness $d$ has a refractive index $n(z)$ that increases with $z$. Here, $z$ is the vertical distance inside the slab, measured from the top. The slab is placed between two media with uniform refractive indices $n _1$ and $n _2\left(>n _1\right)$, as shown in the figure. A ray of light is incident with angle $\theta _i$ from medium 1 and emerges in medium 2 with refraction angle $\theta _f$ with a lateral displacement $l$.
(2016 Main)
Which of the following statement(s) is (are) true? (a) $l$ is independent on $n(z)$
(b) $n _1 \sin \theta _i=\left(n _2-n _1\right) \sin \theta _f$
(c) $n _1 \sin \theta _i=n _2 \sin \theta _f$
(d) $l$ is independent of $n _2$
Show Answer
Answer:
Correct Answer: 33.(a, c, d)
Solution:
Formula:
Laws of Refraction (at any Refracting Surface):
- From Snell’s law,
$n \sin \theta=$ constant
$\therefore n _1 \sin \theta _i=n _2 \sin \theta _f$
Further, $l$ will depend on $n _1$ and $n(z)$. But it will be independent of $n _2$.
BETA
