Q: In the nuclear emission stated above, the mass number and atomic number of the product Q respectively, are

aligned & A 286 \\ & Z=81 aligned

Question 1

Four statements are given (A is mass number) : A. The volume of a nucleus is proportional to A^ 1/3 . B. The volume of a nucleus is proportional to A. C. The difference in mass of an atom and its nucl

Accepted Answer

The radius of a nucleus is given by R = R_0 A^ 1/3 . The volume of the nucleus is V = 4 3 R^3 = 4 3 R_0^3 A. Thus, the volume of a nucleus is directly proportional to its mass number A. Statement A is false and Statement B is true. The mass defect is defined as the difference between the sum of the masses of the constituent nucleons (protons and neutrons) and the actual mass of the nucleus. Thus, Statement C is false and Statement D is true. Therefore, B and D are true, but A and C are false. An

Question 2

Consider the following nuclear reaction : ^ 238 U ^ 234 Th + ^4 He Take masses of ^ 238 U , ^ 234 Th and ^4 He as 238.050 u, 234.043 u and 4.003 u, respectively. The Q value for the reaction, in keV,

Accepted Answer

The mass defect m for the given nuclear reaction is: m = m(^ 238 U ) - [m(^ 234 Th ) + m(^4 He )] m = 238.050 - (234.043 + 4.003) m = 238.050 - 238.046 = 0.004 u The Q value of the reaction is given by: Q = m 931.5 MeV Q = 0.004 931.5 MeV Q = 3.726 MeV Converting to keV: Q = 3.726 10^3 keV = 3726 keV Answer: 3726

Question 3

Select the correct statements among the following : A. Slow neutrons can cause fission in _ 92 ^ 235 U than fast neutrons. B. -rays are Helium nuclei. C. -rays are fast moving electrons or positrons.|

Accepted Answer

(A) Slow neutron can cause fission in _ 92 ^ 235 U than fast neutrons because fast neutrons are too quick so they scatter of atoms instead of being captured by them (B) -rays are Helium nuclei, is a true statement (C) -rays are generated when neutron is converted into proton by releasing electron or proton is converted into neutron by releasing positron. (D) -rays have higher energies as compared to X -rays. So they have smaller wavelength as compared to X-rays.

Question 4

Water is used as a coolant in a nuclear reactor because of its

Accepted Answer

Water is used as a coolant in nuclear reactor because of its high specific heat capacity.

Question 5

In the nuclear emission stated above, the mass number and atomic number of the product Q respectively, are

Accepted Answer

aligned & A 286 \ & Z=81 aligned

Nuclear Physics — Previous Year Questions & Solutions