List of top Physics Questions on spherical lenses asked in NEET (UG)

A small telescope has an objective of focal length 140 cm and an eye piece of focal length 5.0 cm. The magnifying power of telescope for viewing a distant object is :

A point object is placed at a distance of $60\, cm$ from a convex lens of focal length $30\, cm$. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of $40\, cm$ from it, the final image would be formed at a distance of :

A double convex lens has focal length 25 cm. The radius of curvature of one of the surfaces is double of the other. Find the radii if the refractive index of the material of the lens is 1.5 :

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 $(p = 1.5)$ as that of glass) then the equivalent focal length is $F_2$. The ratio $F_1$ : $F_2$ will be :

Two identical glass $(\mu_g = 3/2)$ equiconvex lenses of focal length $f$ each are kept in contact. The space between the two lenses is filled with water $(\mu_w = 4/3)$. The focal length of the combination is

Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index 1.7. The focal length of the combination is

If a convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined together, what will be their resulting power?