Atoms Molecules Nuclei Electrons Photons Test Online

1. Which one of the following is used as a moderator in nuclear reaction?

2. In the nuclear reaction, there is a conservation of:

3. When radioactive substance emits an α-particle, then its position in the periodic table is lowered by:

4. The radius of hydrogen atom in the first excited level is:

5. A radioactive substance decays to 1/16^th of its initial activity in 40 days. The half-life of the radioactive substance expressed in days is

6. The surface of zone material is radiated in turn by waves of λ = 350 nm and 540 nm respectively. The ratio of the stopping potential in the two cases is 2:1. The work function of the material is

7. A proton is about 1840 times heavier than an electron. When it is accelerated by a potential difference of 1 kV, its kinetic energy will be

8. The reaction responsible for the production of light energy from the sun will be:

9. In each fission of ₉₂U²³⁵ releases 200 MeV, how many fission's must occur per second to produce power of 1 kW?

10. In ₈₈Ra²²⁶ nucleus there are:

11. If the radioactive decay constant of radium is 1.07 x 10⁻⁴ per year. Then its half life period approximately is equal to:

12. Particle nature and wave nature of electromagnetic waves and electrons can be represented by:

13. The activity of a radioactive sample is 1.6 curie and its half life is 2.5 days. Then activity after 10 days will be:

14. When cathode rays strike a metal target of high melting point with a very high velocity then which of the following are produced ?

15. In an atom bomb, the energy is released because of the: