Nuclei

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

A nucleus of uranium decays at rest into nuclei of thorium and helium. Then

1. The helium nucleus has more momentum than the thorium nucleus.
2. The helium nucleus has less kinetic energy than the thorium nucleus.
3. The helium nucleus has more kinetic energy than the thorium nucleus.
4. The helium nucleus has less momentum than the thorium nucleus.

If radius of the 2713Al nucleus is taken to be RAl, then the radius of 12553Te nucleus is nearly

1. 35 RAl
2. ( 1353 )1/3 RAl
3. ( 5313 )1/3 RAl
4. 53 RAl

The binding energy per nucleon of 73Li and 42He nuclei are 5.60 MeV and 7.06 MeV respectively. In the nuclear reaction 73Li + 11H 42He + 42He + Q the value of energy Q released is

1. 19.6 MeV
2. -2.4 MeV
3. 8.4 MeV
4. 17.3 MeV