Two thin lenses of focal length f1 and f2 are in contact and coaxial. The power of the combination is Two thin lenses of focal length f1 and f2 are in contact and coaxial. The power of the combination is August 20, 2020 Category: Chapter 32 - Ray Optics , NEET Last 32 Years Solved 1988 - 2019 Physics and Chemistry Video Solutions , Physics , Facebook Messenger WhatsApp Share this:TwitterFacebook Related Two similar thin equi-convex lenses, of focal length f each, are kept co-axially 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 beA thin prism having refracting angle 10 degree is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of second prism should beTwo thin doubled convex lenses of focal length f1 = 24, f2 = 11 cm are placed a part by a distance of 10 cm. An object is placed in front of f1 at a distance of O1 = 8 cm on the axis of the lens combination. What is the nature and distance from f2 of the final image ?