ATOMIC NUCLEUS – Question Bank


1. Draw a labelled diagram of Geiger – Marsden experiment on scattering of α particles. How is the size of the nucleus estimated in this experiment.

2. Which particles constitute the nucleus.

3. Distinguish between mass number and atomic number.

4. What are isotopes? Give one example.

5. What are isotopes? Give one example.

6. What are isobars? Give example.

7. How is the radius of a nucleus related to its mass number?

8. What is the ratio of the radii of two nuclei of mass numbers A1 and A2 ?

9. How does the nuclear density depend on the size of the nucleus?

10. Who discovered neutrons? Write the nuclear reaction.

11. Is free neutron stable’?

12. What is natural radioactivity?

13. Arrange α, β and γ rays in order of increasing ionizing power.

14. What is the practical unit of rate of decay (activity)?

15. What are radioisotopes?

16. A radioactive nucleus undergoes a series of decays according to the sequence


If the mass number and atomic number of A3 are 172 and 69, respectively, what are the mass number and atomic number of A?

17. Write the important properties of neutrons.

18. What do you mean by alpha decay?

19. What is beta decay?

20. Write the equation of beta decay of a neutron.

21. What are gamma rays?

22. Define one roentgen.

23. Which part of the atom is responsible for radioactivity?

24. Arrange alpha. beta and gamma rays in the decreasing order of their penetrating power

25. For which of the nuclear radiations a, 13 or a, the path is not affected by an electric field and why?

26. In a magnetic field, the radius of the circular path of β particles is more than the that of the path of α particles. Why?