(a) Under what conditions is the phenomenon of total internal reflection of light observed? Obtain the relation between the critical angle of incidence and the refractive index of the medium.
(b) Three lenses of focal lengths `+10cm,-10cm and +30cm` are arranged coaxially as in the figure given below. Find the position of the final image formed by the combination.

(b) (i) Write a balanced equation showing nuclear fission of Uranium `(""_(92)^(235)U)` nucleus.
(ii) In a nuclear reactor, what is the function of :
(a) Cadmium rods? (b) Graphite rods?

Explanation

(a) calculate `Deltam` = mass of nucleons - mass of nucleus
Binding energy = `Deltamxx931.5` (in MeV).
(b) Learn the charateristics of X-rays and continuous X-rays.