10 Question-answer on Physics of nucleus and radioactivity
1. The neutron was discovered by
(a) Marie curie
(b) Pierre curie
(c) James Chadwick
(d) Rutherford
Ans: ( c)
2. The mass number of a nucleus is
(a) Always less than its atomic number
(b) Always more than its atomic number
(c) Sometimes equal to its atomic number
(d) Sometimes more than and sometimes equal to its atomic number.
Ans: ( d)
3. When the number of nucleons in nuclei increase, the binding energy per nucleon
(a) Increases continuously with mass number
(b) decreases continuously with mass number
(c) remains constant with mass number
(d) First increases and then decreases with increase of mass number.
Ans: ( d)
4. Radioactivity is
(a) Irreversible process
(b) Self disintegration process
(c) Spontaneous
(d) All of above.
Ans: (d)
5. Beta rays emitted by a radioactive material are
(a) Electromagnetic radiations
(b) The electrons orbiting around the nucleus
(c) Charged particles emitted by nucleus
(d) Neutral particles
Ans: (c)
6. What fissionable material was used in the bomb dropped at Nagasaki (Japan) in the year 1945?
(a) Uranium
(b) Neptunium
(c) Berkelium
(d) Plutonium
Ans: ( d)
7. Half life radioactive element depends upon
(a) Amount of element present
(b) Temperature
(c) Pressure
(d) None of the above
Ans: (d)
8. The alpha and beta particles cause ionization because of
(a) Photo-electric emission
(b) Compton collision
(c) Pair production
(d) The electrostatic force.
Ans: (d)
9. Particles which can be added to the nucleus of an atom without changing its chemical properties are called
(a) Neutrons
(b) Electrons
(c) Protons
(d) Alpha particles
Ans: (a)
10. Which of the following is not a mode of radioactive decay
(a) Positron emission
(b) Electron capture
(c) Fusion
(d) Alpha decay
Ans: (c)