Two similar thin equi-convex lenses, of focal f each, are kept coaxially in contact with each other such that the focal length of the combination is F₁. When the space between the two lenses is filled with glycerin (which has the same refractive index (µ = 1.5) as that of glass) then the equivalent focal length is F2. The ratio F₁: F₂ will be - VgyanHub

Question:

Two similar thin equi-convex lenses, of focal f each, are kept coaxially in contact with each other such that the focal length of the combination is F₁. When the space between the two lenses is filled with glycerin (which has the same refractive index (µ = 1.5) as that of glass) then the equivalent focal length is F2. The ratio F₁: F₂ will be

Options :

(a) 3:4
(b) 2:1
(c) 1:2
(d) 2:3

Answer :

(c) 1:2

Answer Steps :

step 1

step 2

step 3

Video Tutorial

Related Questions

An alternating voltage source is connected in series with a resistance R and an inductance L. If the potential drop across the resistance is 200 V and across the inductance is 150 V, then the applied voltage is:

A 1 µF condenser is charged to 50 V. The charging battery is then disconnected and a 10 mH coil is connected across the capacitor so that LC oscillations occur. What is the maximum current in the coil ? Assume that the circuit contains no resistance. The capacity of a pure capacitor is 1 F. In d.c. circuits, its effective resistance will be

In an a. c. circuit the instantaneous current and e.m.f. are represented as: I = I0 sin(ωt – π/6) and E = E0 sin(ωt + π /3) respectively. The voltage leads the current by

Explore Our Courses