JEE Advanced · 2007 · 08 Apr 2007 · Paper 1 · Modern Physics

In the options given below, let

E

denote the rest mass energy of a nucleus and

n

a neutron. The correct option is

(A) $E (_{92}^{236} U) > E (_{53}^{137} I) + E (_{39}^{97} Y) + 2 E (n)$ ✓ Correct
(B) $E (_{92}^{236} U) < E (_{53}^{137} I) + E (_{39}^{97} Y) + 2 E (n)$
(C) $E (_{92}^{236} U) < E (_{56}^{140} B a) + E (_{36}^{94} K r) + 2 E (n)$
(D) $E (_{92}^{236} U) = E (_{56}^{140} B a) + E (_{36}^{94} K r) + 2 E (n)$

Answer: (A)

Solution

In nuclear fission, a heavy nucleus splits into lighter fragments, releasing energy. This energy comes from the mass defect — the rest mass energy of the parent nucleus is greater than the sum of the rest mass energies of the products.

For the fission of

^{236} U

, energy is released, which means:

E (^{236} U) > E (products)

Therefore, option (A) is correct: the rest mass energy of

^{236} U

is greater than the sum of the rest mass energies of the fission products plus neutrons.

JEE Advanced · 2007 · 08 Apr 2007 · Paper 1 · Single correct option

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JEE Advanced · 2007 · 08 Apr 2007 · Paper 1 · Modern Physics

Solution

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