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3 C 20226

The disintegration constant 7. of a radioactive element is 0.00231 per day. Calculate its half-life
and average life.

A reactor is developing energy at the rate of 3000 kW. How many atoms of U2” undergo fission
per second ?

Briefly explain equatorial and ecliptic co-ordinate systems.
List the four fundamental interaction and their properties.
(4 x 4= 16 marks)
Section E (Essays—Answer in about two pages)

Answer any two questions.

Each question carries 10 marks.

Give the principle of nuclear reactor. What are the roles of moderator and control rods in the

reactor ? List the main parts and explain the working of the reactor.

Discuss the origin and nature of cosmic rays. Differentiate between primary and secondary cosmic
rays. Explain properties of beta and gamma rays.

Explain liquid drop model of nucleus. How does it lead to the semi-empirical mass formula. Write
any two application of Semi-empirical mass formula.

Explain the classification of elementary particles with examples.

(2 x 10 = 20 marks)

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