Interference is possible in

The hypermetropia is a

Rainbows are formed by

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 :

Light travels through a glass plate of thickness t and refractive index μ. If c is the speed of light in vacuum  the time taken by light to travel this thickness of glass is :

For the given incident ray as shown in figure, the condition of total internal reflection of the ray will be satisfied if the refractive index of block will be

Which of the following phenomenon is not common to sound and light waves?

A telescope has an objective lens of 10cm diameter and is situated at a distance of one kilometre from two objects. Find out the minimum distance between these two objects, which can be resolved by the telescope, when the mean wavelength of light is 5000 Å.

If two mirrors are kept inclined at 60° to each other and a body is placed at the middle, then total number of images formed is :

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?