Two similar thin equi-convex lenses of focal length f each are kept coaxially in contact with each other, such that the focal length of the combination is F 1 . 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…

Question

Two similar thin equi-convex lenses of focal length f each are kept coaxially in contact with each other, such that the focal length of the combination is F 1 . 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 F 2 . The ratio F 1 : F 2 will be

Aicharya · Accepted Answer

Case I: 1 F eq + 1 F + 1 F F 1 = F eq = F 2 Case II: F 2 = F eq = F F 1 : F 2 = 1 : 2

Two similar thin equi-convex lenses of focal length f each are kept coaxially in contact with each other,…

Solution