Question

In the options given below, let $$E$$ denote the rest mass energy of a nucleus and $$n$$ a neutron. The correct option is

A. \[E\left( {\begin{array}{*{20}{c}} {236}\\ {92} \end{array}U} \right) > E\left( {\begin{array}{*{20}{c}} {137}\\ {53} \end{array}I} \right) + E\left( {\begin{array}{*{20}{c}} {97}\\ {39} \end{array}Y} \right) + 2E\left( n \right)\]  
B. \[E\left( {\begin{array}{*{20}{c}} {236}\\ {92} \end{array}U} \right) < E\left( {\begin{array}{*{20}{c}} {137}\\ {53} \end{array}I} \right) + E\left( {\begin{array}{*{20}{c}} {97}\\ {39} \end{array}Y} \right) + 2E\left( n \right)\]
C. \[E\left( {\begin{array}{*{20}{c}} {236}\\ {92} \end{array}U} \right) < E\left( {\begin{array}{*{20}{c}} {140}\\ {56} \end{array}Ba} \right) + E\left( {\begin{array}{*{20}{c}} {94}\\ {36} \end{array}Kr} \right) + 2E\left( n \right)\]
D. \[E\left( {\begin{array}{*{20}{c}} {236}\\ {92} \end{array}U} \right) = E\left( {\begin{array}{*{20}{c}} {140}\\ {56} \end{array}Ba} \right) + E\left( {\begin{array}{*{20}{c}} {94}\\ {36} \end{array}Kr} \right) + 2E\left( n \right)\]
Answer :   \[E\left( {\begin{array}{*{20}{c}} {236}\\ {92} \end{array}U} \right) > E\left( {\begin{array}{*{20}{c}} {137}\\ {53} \end{array}I} \right) + E\left( {\begin{array}{*{20}{c}} {97}\\ {39} \end{array}Y} \right) + 2E\left( n \right)\]
Solution :
Iodine and Yttrium are medium sized nuclei and therefore, have more binding energy per nucleon as compared to Uranium which has a big nuclei and less B.E/nucleon.
In other words, Iodine and Yttrium are more stable and therefore possess less energy and less rest mass. Also when Uranium nuclei explodes, it will convert into $$I$$ and $$Y$$ nuclei having kinetic energies.

Releted MCQ Question on
Modern Physics >> Radioactivity

Releted Question 1

An alpha particle of energy $$5\,MeV$$  is scattered through $${180^ \circ }$$ by a fixed uranium nucleus. The distance of closest approach is of the order of

A. $$1\, \mathop {\text{A}}\limits^ \circ $$
B. $${10^{ - 10}}cm$$
C. $${10^{ - 12}}cm$$
D. $${10^{ - 15}}cm$$
Releted Question 2

Beta rays emitted by a radioactive material are

A. electromagnetic radiations
B. the electrons orbiting around the nucleus
C. charged particles emitted by the nucleus
D. neutral particles
Releted Question 3

Consider $$\alpha $$ particles, $$\beta $$ particles and $$\gamma $$ - rays, each having an energy of $$0.5\,MeV.$$  In increasing order of penetrating powers, the radiations are:

A. $$\alpha ,\beta ,\gamma $$
B. $$\alpha ,\gamma ,\beta $$
C. $$\beta ,\gamma ,\alpha $$
D. $$\gamma ,\beta ,\alpha $$
Releted Question 4

A radioactive material decays by simultaneous emission of two particles with respective half-lives 1620 and 810 years. The time, in years, after which one-fourth of the material remains is

A. 1080
B. 2430
C. 3240
D. 4860

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Radioactivity


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