Sunday, 28 September 2014


6. The kinetic energy of electron in the first Bohr orbit of the hydrogen atom is. [Pb. PET 2000]

7. If the ionisation potential of helium atom is 24.6 volt, the energy required to ionise it will be. [MP PMT 1996]

8. The particles which can be added to the nucleus of an atom without changing its chemical properties are called. [NCERT 1979]

9. When hydrogen atom is in its first excited level, its radius is .... its ground state radius. [CBSE PMT 1997]

10. When a hydrogen atom is raised from the ground state to an excited state. [CBSE PMT 1995; ]

11. The frequency of 1st line of Balmer series in H₂ atom is v₀ The frequency of line emitted by singly ionised He atom is. [CPMT 2002]

12. The spectral series of the hydrogen spectrum that lies in the ultraviolet region is the. [CPMT 1990; MP P]

13. In the spectrum of hydrogen atom, the ratio of the longest wavelength in Lyman series to the longest wavelength in the Balmer series is. [UPSEAT 2004]

14. The half life of a radioactive element which has only 1/32 of its original mass left after a lapse of 60 days is.[MP PET 1992; DP]

15. The decay constant of a radioactive element is 0.01 per second. Its half life period is. [DPMT 2001]

16. The Lyman series of hydrogen spectrum lies in the region. [UPSEAT 2002]

17. The wavelength of yellow line of sodium is 5896 Å. Its wave number will be. [MP PET 2001]

18. Half life of radioactive element depends upon. [NCERT 1978; AFM]

19. In any Bohr orbit of the hydrogen atom, the ratio of kinetic energy to potential energy of the electron is. [MP PET 1994]

20. In the above figure D and E respectively represent. [CPMT 1986, 88]