Nuclei · Question 9

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

1. Statement I is incorrect but statement II is correct
2. Both statement I and statement II are correct
3. Both statement I and statement II are incorrect
4. Statement I is correct but statement II is incorrect

At any instant, two elements X1 and X2 have same number of radioactive atoms. If the decay constant of X1 and X2 are 10 and respectively, then the time when the ratio of their atoms becomes 1e respectively will be :

1. 15
2. 111
3. 19
4. 16

A nucleus with mass number 240 breaks into two fragments each of mass number 120, the binding energy per nucleon of unfragmented nuclei is 7.6 MeV while that of fragments is 8.5 MeV. The total gain in the Binding Energy in the process is :

1. 216 MeV
2. 0.9 MeV
3. 9.4 MeV
4. 804 MeV

The half life of a radioactive nuclide is 100 hours. The fraction of original activity that will remain after 150 hours would be :

1. 23 2
2. 12
3. 12 2
4. 23

A radioactive nucleus ZAX Z-1B Z-3C Z-2D, where Z is the atomic number of element X. The possible decay particles in the sequence are :

1. -, , +
2. , -, +
3. , +, -
4. +, , -

The energy equivalent of 0.5 g of a substance is :

1. 4.5 1013 J
2. 1.5 1013 J
3. 0.5 1013 J
4. 4.5 1016 J

When a uranium isotope 23592U is bombarded with a neutron, it generates 8936Kr, three neutrons and :

1. 9140Zr
2. 10136Kr
3. 10336Kr
4. 14456Ba

For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is

1. 20
2. 10
3. 30
4. 15

Radioactive material 'A' has decay constant '8 ' and material 'B' has decay constant ' '. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that of 'A' will be e ?

1. 17
2. 18
3. 19
4. 1

The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is

1. 15
2. 30
3. 45
4. 60