A convex lens of refractive index 1.5 has a focal length of 18 cm in air.Calculate the change in focal length,when it is immersed in water of refractive index `4//3`.

A converging lens has a focal length of 20 cm in air. It is made of a material of refractive index 1.6. If it is immersed in a liquid of refractive index 1.3, what will be the new focal length? How does the nature of the lens change. If this lens is immersed is a liquid of refractive index 1.8 ?

A double convex lens has 10 cm and 15 cm as its two radii of curvature.The image of an object,placed 30 cm from the lens,is formed at 20 cm from the lens on the other side.Find the refractive index of the material of the lens.Whgat will be the focal length ?What will be the focal length of the lens,if it is immersed in water of refractive index 1.33?

What happens to be focal length of convex lens when it is immersed in water?

A convex lens of refractive index 1.5 is immersed in a liquid of refractive index: 1.6 What will happen to the focal length and nature of lens ?

The radii of curvature of a convex lens are 20 cm and 30 cm nd the refractive index of its material is 1.5 .How its nature nd focal length will change ,when it is immersed in a liquid of refractive index = 1.6?

Focal length of a convex lens of refractive index 1.5 is 2 cm.Focal length of lens,when immersed in a liquid of refractive index of 1.25 will be