Nuclei

A sample of radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the sample after two mean lives is

1. 1.35 g
2. 2.50 g
3. 3.70 g
4. 6.30 g

The mass number of a nucleus is

1. always less than its atomic number
2. always more than its atomic number
3. sometimes equal to its atomic number
4. sometimes less than and sometimes more than its atomic number

A nuclear reaction given by ZXA Z+1YA + -1e0 + represents

1. -decay
2. -decay
3. fusion
4. fission

Which of the following are suitable for the fusion process?

1. light nuclei
2. heavy nuclei
3. elements lying in the middle of the periodic table
4. middle elements, which are lying on binding energy curve.

A deuteron is bombarded on 8O16 nucleus, then an -particle is emitted. The product nucleus is

1. 7N13
2. 5B10
3. 4Be9
4. 7N14

A sample of radioactive element containing 4 1016 active nuclei. Half-life of element is 10 days, then number of decayed nuclei after 30 days

1. 0.5 1016
2. 2 1016
3. 3.5 1016
4. 1 1016

X(n, ) 73Li, then X will be

1. 105B
2. 95B
3. 114Be
4. 42He

Mn and Mp represent the mass of neutron and proton respectively. An element having mass M has N neutrons and Z protons, then the correct relation will be

1. M < \N Mn + Z Mp\
2. M > \N Mn + Z Mp\
3. M = \N Mn + Z Mp\
4. M = N\Mn + Mp\

Energy released in nuclear fission is due to

1. some mass is converted into energy
2. total binding energy of fragments is more than the binding energy of parental element
3. total binding energy of fragments is less than the binding energy of parental element
4. total binding energy of fragments is equal to the binding energy of parental element

Which rays contain (positive) charged particles?

1. -rays
2. -rays
3. -rays
4. X-rays