A double convex lenses glass of a refractive index 1.6 has its both surfaces of equal radii of curvature 30 cm each. Find focal length of the lens.

A plano-convex lens is made of refractive index 1.6.If the radius of curvature of the curved surface is 60 cm,then focal length of the lens is:

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.

A double convex lens made of glass of refactive index 1.56 has both radii of curvature of magnitude 20 cm.If an object is placed at a distance of 10 cm from this lens,find the positiojn of the image formed.

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 2.0 cm long needle is placed vertically at a distance 48 cm in front of a double convex lens made of a material of refractive index 1.5 having radii of curvature as 20 cm and 30 cm. Find the height of image formed.

Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20cm?

A binoconves lens with both faces of the same radius of curvature is to be manufatured from a glass of refractive index 1.55.What should be the radius of curvature for the focal length of the lens to be 20 cm?