Atoms Molecules Nuclei Electrons Photons Test Online

1. The flux of α-particle at angle 60° is

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

3. 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:

4. Half life of a substance is 20 minutes and then the time between 33% decay and 67 % decay will be

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

7. X-ray will not show the phenomenon of

8. In Bohr’s theory, relation between principal quantum number n and radius of orbit r is:

9. 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

10. The kinetic energy of an electron, which is accelerated in the potential difference of 100 V, is:

11. If the electron in hydrogen orbit jumps from third orbit to second orbit, the wavelength of the emitted radiation is given by:

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

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

14. The speed of an electron having a wavelength of 10⁻¹⁰ m is:

15. For an electron in the second orbit of hydrogen the moment of momentum as per Bohr’s model is