PhysicsHardHigh School (11–12)Optics › Lenses and Optical InstrumentsJEE MainNEETAEEE (Amrita)AMUEEEAP EAPCETBCECE
Created by StemPy LabA student has a thin double convex lens of refractive index . Its focal length in air is . She holds it completely under a transparent liquid of refractive index and sends a narrow beam of parallel rays from a distant lamp along its axis. What is the focal length of the lens in the liquid, and what does the lens do to the beam?
← All Quizzes
← Six statements about total internal reflection are given below. (i) A diamond sparkles because its critical angle is small. (ii) In an optical fibre, the cladding is denser than the core. (iii) A fibre guides light by total reflection at its core. (iv) A right-angled isosceles glass prism (n = 1.50) turns a ray, entering normally, through 90°. (v) Light going from air into glass can be totally reflected. (vi) Glass has a smaller critical angle in water than in air. How many of the statements above are correct?Assertion (A): A small air bubble inside a glass block has the shape of a double convex lens. A narrow parallel beam of light that travels through the block and falls on the bubble along its axis spreads out after passing through it.
Reason (R): A lens of a given shape bends light towards its axis only if its material has a larger refractive index than its surroundings. If the material has a smaller index, the same shape bends light away from the axis. →
Discussion (0)
Log in to join the discussion.
Loading…