What is chromatic aberration? How can it be minimized or eliminated ?

What is reverberation ? How can it be reduced ?

What is permutit method, how can it be used for softening hard water?

What is meant by : (1) Spherical aberration ? (2) Chromatic aberration ? (ü) How can spherical aberration be reduced/ minimized ? Suggest any one method.

What is the main reason for axial charomatic aberration in the formation of image by an lens ?

What is deionised water and how can it be prepared?

What is polyembryony and how can it be commercially exploited?

What is Joule's heating effect ? How can it be demonstrated experimentally ? List its four applications in daily life.

A convex lens has mean focal length of 20 cm. The dispersive power of the material of the lens is 0.02. The longitudinal chromatic aberration for an object at infinity is

A convex lens has mean focal length of 20 cm. The dispersive power of the material of the lens is 0.02. The longitudinal chromatic aberration for an object at infinity is

What causes asthma? How can it be treated?