If a lens of refractive index μ is immersed in a medium of refractive index μ1, then its focal length in medium is given by fm1=(mμl−1(R11)−R21) If fa is the focal length of lens in air, then fa1=(aμl−1(R11−R21)⇒fafm=(mμl−1)(aμl−1) If μ1>μ, then fm and fa have opposite signs and the nature of lens changes i.e. a convex lens diverges the light rays and concave lens converges the light rays. Thus given option (a) is correct.
JEE Main 2014 — Physics Optics
2014mcqeasy
The refractive index of the material of a concave lens is μ. It is immersed in a medium of refractive index μ1. A parallel beam of light is incident on the lens. The path of the emergent rays when μ1>μ is:
Official previous-year question
Held on 12 Apr 2014 · Verified 6 Jul 2026.
Options
- A
- B
- C
- D
Did you get this right?
Sign in to track your attempts and accuracy.
Your note
Sign in to keep a private note on this question. Nothing you write is ever public.
JEE Main Optics in other years
More JEE Main Optics questions
Which of the following are true for a single slit diffraction? A. Width of central maxima increases with increase in wavelength keeping slit width constant. B. Width of central maxima increases with decrease in wavelength keeping slit width constant. C. Width of central maxima increases with decrease in slit width at constant wavelength. D. Width of central maxima increases with increase in slit width at constant wavelength. E. Brightness of central maxima increases for decrease in wavelength at constant slit width.
2026medium
In parallax method for the determination of focal length of a concave mirror, the object should always be placed:
2026easy
A slit of width $a$ is illuminated by light of wavelength $\lambda$. The linear separation between $1^{st}$ and $3^{rd}$ minima in the diffraction pattern produced on a screen placed at a distance $D$ from the slit system is _____.
2026easy
A beam of light consisting of wavelengths 650 nm and 550 nm illuminates the Young's double slits with separation of 2 mm such that the interference fringes are formed on a screen, placed at a distance of 1.2 m from the slits. The least distance of a point from the central maximum, where the bright fringes due to both the wavelengths coincide, is $\_\_\_\_$ $\times 10^{-5} \mathrm{~m}$.
2026medium
A thin prism with angle $5^{\circ}$ of refractive index 1.72 is combined with another prism of refractive index 1.9 to produce dispersion without deviation. The angle of second prism is $\_\_\_\_$.
2026easy
Other Physics topics for JEE Main
Keep practicing Optics
Work through every JEE Main Optics PYQ, year by year.