JEE PYQ: Ray Optics Question 47
Question 47 - 2019 (10 Jan Shift 2)
The eye can be regarded as a single refracting surface. The radius of curvature of this surface is equal to that of cornea (7.8 mm). This surface separates two media of refractive indices 1 and 1.34. Calculate the distance from the refracting surface at which a parallel beam of light will come to focus.
(1) 1 cm
(2) 2 cm
(3) 4.0 cm
(4) 3.1 cm
Show Answer
Answer: (4)
Solution
using $\frac{\mu_1}{v} - \frac{\mu_2}{u} = \frac{\mu_2 - \mu_1}{R}$ $R = 7.8$ mm $\mu_1 = 1$, $\mu_2 = 1.34$ $\Rightarrow \frac{1.34}{V} - \frac{1}{\infty} = \frac{1.34 - 1}{7.8}$ $[\because u = \infty]$ $\therefore V = 30.7$ mm $= 3.07$ cm $\approx 3.1$ cm
BETA
