A small object is placed 50 m in front of a convex surface of radius 20 m. If the surface separates air from glass of refractive index 1.5, find the power of the surface.

An object is placed 21 cm in front of a concave mirror of radius of curvature 10 cm.A glass slab of thickness 3 cm and refractive index 1.5 is then placed close to the irror in the space between the object and mirror as shown in Fig.2.62.Find the position of the final image formed.You may take the distacne of the near surface of the slab from the mirror to be 1 cm. .

An object is placed 30 cm in front of a plano-convex lens with its spherical surface of radius of curvature 20 cm. If the refractive index of the material of the lens is 1.5, find the position and nature of the image formed.

A small point object is placed in air at a distance of 60 cm from the convex spherical refracting surface of refractive index 1.5.If radius of curvatrure of the spherical surface is 25 cm,calculate the power of the refracting surface.

A pin is placed 10 cm in front of convex lens of focal lenth 20 cm made of material of refractive index 1.5 .the surface of the lens farther away from the pin is silvered and has a radius curvature 22 cm.Detrermine the position of the final image.Is the image real or virtual? .

A 5.0 cm long needle is placed vertically at a distance 20 cm in front of a double convex lens made of a material of refractive index 1.5 having radii of curvature as 10 cm of each surface. Find theheight of image formed.

A 3.0 cm long needle is placed vertically at a distance 50 cm in front of a double convex lens made of a material of refractive index 1.6 having radii of curvature as 30 cm of each surface. Find the height of image formed by the lens.

What is the focal length of a double convex lens for which radius of curvature of the surfaces is 40 cm and refractive index of the glass is 1.5?

The radius of curvature of each face of a biconcave lens made of glass of refractive index 1.5 is 30 cm. Calculate the focal length of the lens is air.

Find the surface area of a sphere of diameter: 3.5m