Write the uses of radio isotopes in

(a) agriculture

(b) industries.

Two lenses have power of

(a) +2 D and

(b) -4 D

What is the nature and focal length of each lens?

The diagram below shows a point source P inside a water container. Four rays A, B, C and D starting from the source P are shown upto the water surface.

(a) Show in the diagram, the path of these rays after striking the water surface. The critical angle for water-air surface is 48°.

(b) Name the phenomenon which the rays B and D exhibit.

(c) Can total internal reflection occur when rays travel from rarer medium to denser medium?

Name three factors on which the deviation produced by a prism depends and state how does it depend on the factors stated by you.