(i) Write a balanced equation showing nuclear fission of Uranium 

(ii) In a nuclear reactor, what is the function of:

(1) Cadmium rods? (2) Graphite rods?

42. Starting with N = N₀e^-λt, obtain a relation between disintegration constant ‘λ’ of a radioactive element and its half life (T), various terms have their usual meaning.

On an energy level diagram of hydrogen, show by a downward or an upward arrow, a transition which results in:

(i) Emission line of Balmer series.

(ii) Emission line of Lyman series.

(iii) Absorption line of Lyman series.

Calculate:

i) Mass defect of helium   and 
ii) 

Its binding energy in MeV.

Mass of a proton = 1.007276 u

Mass of a neutron = 1.008665 u

Mass of  nucleus = 4.001506 u