VERY SHORT ANSWER TYPE QUESTIONS

1. Draw a labeled diagram of Gieger - Marsden Experiment on scattering of α particle. 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 is isotones? 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 number 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 neutrons 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    ***
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 α ,β or γ ,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 ?
27. What is meant by activity of a radioactive sample ?
28. Electrons do not exist inside the nucleus . How is emission of electrons possible from the nucleus of a radioactive substance ?
29. A radio active atom having atomic number Z and mass number A decays by emission of an electron.Write down the atomic number and mass number of the new element ?
30. How many α particles will be emitted in the decay ²²⁴₉₀ Th
31. Is the daughter nucleus formed after the emission of a  β particle an isotope or an isobar of  the parent nucleus ?
32. Define disintegration constant and mean life of a radioactive substance. Give the units of each
33. Name the heaviest stable nuclide.
34. Does the ratio of neutron to proton in a nucleus increase , decrease  or remain the same after the emission of an   α particle?
35. Name two elementary particles which are stable .
36. Define curie . Give its relation with Rutherford .
37. Why  γ decay generally follows α or β decay ?
38. Define half life of a radioactive material ?
39. Define decay constant λ of  a radioactive substance . How is it relate to half life ?
40. Define atomic mass unit ?
41. What is the energy equivalent