Nuclei

Two radioactive substances A and B of mass numbers 200 and 212 respectively, shows spontaneous -decay with same Q value of 1 MeV. The ratio of energies of -rays produced by A and B is .

1. 25482650
2. 27062646
3. 25972600
4. 28622499

The energy released if hydrogen atoms are combined to form 24He is MeV. (Take binding energies per nucleon of 12H and 24He as 1.1 MeV and 7.2 MeV, respectively)

1. 6.1
2. 24.4
3. 26.6
4. 5

Assuming the experimental mass of 612C as 12 u, the mass defect of 612C atom is MeV/c2. (Mass of proton = 1.00727 u, mass of neutron = 1.00866 u, 1 u = 931.5 MeV/c2 and c is the speed of the light in vacuum).

1. 127.5
2. 89.03
3. 272.0
4. 92.0

Two nuclei of mass number 3 combine with another nucleus of mass number 4 to yield a nucleus of mass number 10. If the binding energy per nucleon for the mass numbers 3, 4 and 10 are 5.6 MeV, 7.4 MeV and 6.1 MeV, respectively, then in the process, Mc2= MeV.

1. 6.9
2. 7.9
3. 2.2
4. 4.3

The binding energy per nucleon of 20983Bi is MeV. [Take m( 20983Bi) = 208.980388 u, mp = 1.007825 u, mn = 1.008665 u, 1 u = 931 MeV/c2]

1. 7.48
2. 7.84
3. 8.79
4. 6.94

An atom 83X is bombarded by shower of fundamental particles and in 10 s this atom absorbed 10 electrons, 10 protons and 9 neutrons. The percentage growth in the surface area of the nucleus is recorded by :

1. 150\%
2. 900\%
3. 125\%
4. 225\%

A nucleus has mass number and radius R . Another nucleus has mass number and radius R . If = 8 then R /R is :

1. 1
2. 2
3. 8
4. 0.5

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below

1. Statement I is false but Statement II is true
2. Both Statement I and Statement II are true
3. Both Statement I and Statement II are false
4. Statement I is true but Statement II is false

The binding energies for the following nuclear reactions are expressed in MeV. 2He3 + 0n1 2He4 + 20 MeV 2He4 + 0n1 2He5 - 0.9 MeV If X3, X4, X5 denote the stability of 2He3, 2He4 and 2He5, respectively, then the correct order is :

1. X4 > X5 > X3
2. X4 < X5 < X3
3. X4 > X5 < X3
4. X4 = X5 = X3

Which of the following pair of nuclei are isobars of the element?

1. 31H and 32He
2. 19880Hg and 19779Au
3. 21H and 31H
4. 23692U and 23892U

The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 particles is kHz. [mass of He nucleus = 4.002 amu, 1 amu = 1.66 10-27 kg, h = 6.6 10-34 J s and c = 3 108 m/s]

1. 14.94 1020
2. 9 1019
3. 9 1020
4. 14.94 1019

For a nucleus of mass number A and radius R, the mass density of nucleus can be represented as

1. A 23
2. Independent of A
3. A3
4. A 13

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :

1. (A) is correct but (R) is not correct
2. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
3. (A) is not correct but (R) is correct
4. Both (A) and (R) are correct and (R) is the correct explanation of (A)

A radioactive material P first decays into Q and then Q decays to non-radioactive material R. Which of the following figure represents time dependent mass of P, Q and R ?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Energy released when two deuterons (1H2 ) fuse to form a helium nucleus (2He4 ) is : (Given : Binding energy per nucleon of 1H2 = 1.1 MeV and binding energy per nucleon of 2He4 = 7.0 MeV)

1. 26.8 MeV
2. 8.1 MeV
3. 23.6 MeV
4. 5.9 MeV

Choose the correct nuclear process from the below options [p : proton, n : neutron, e- : electron, e+ : positron, : neutrino, : antineutrino]

1. n p + e+ +
2. n p + e- +
3. n p + e+ +
4. n p + e- +

A radioactive nucleus n2 has 3 times the decay constant as compared to the decay constant of another radioactive nucleus n1. If initial number of both nuclei are the same, what is the ratio of number of nuclei of n2 to the number of nuclei of n1, after one half-life of n1 ?

1. 1/4
2. 1/8
3. 4
4. 8

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the correct answer from the options given below :

1. (A) is true but (R) is false
2. Both (A) and (R) are true and (R) is the correct explanation of (A)
3. (A) is false but (R) is true
4. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)