ATOMIC PHYSICS MCQ CBSE

6. The kinetic energy of electron in the first Bohr orbit of the hydrogen atom is. [Pb. PET 2000] - 6.5 eV 13.6 eV - 27.2 eV - 13.6 eV

7. If the ionisation potential of helium atom is 24.6 volt, the energy required to ionise it will be. [MP PMT 1996] 24.6 eV 13.6 V 24.6 V 13.

8. The particles which can be added to the nucleus of an atom without changing its chemical properties are called. [NCERT 1979] Electrons Neutrons Protons None of the above

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

10. When a hydrogen atom is raised from the ground state to an excited state. [CBSE PMT 1995; ] P.E. increases and K.E. decreases Both kinetic energy and potential energy increase P.E. decreases and K.E. increases Both K.E. and P.E. decrease 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] 2v₀ v₀ / 2 4v₀ v₀ / 4 12. The spectral series of the hydrogen spectrum that lies in the ultraviolet region is the. [CPMT 1990; MP P] Balmer series Paschen series Pfund series Lyman series 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] 5/27 4/9 1/93 3/2 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] 12 days 60 days 32 days 64 days 15. The decay constant of a radioactive element is 0.01 per second. Its half life period is. [DPMT 2001] 693 sec 0.693 sec 6.93 sec 69.3 sec 16. The Lyman series of hydrogen spectrum lies in the region. [UPSEAT 2002] Infrared Ultraviolet Visible Of X rays 17. The wavelength of yellow line of sodium is 5896 Å. Its wave number will be. [MP PET 2001] 50883 × 1010 per second 17581 per cm 16961 per cm 50883 per cm 18. Half life of radioactive element depends upon. [NCERT 1978; AFM] Amount of element present Pressure Temperature Nature of element 19. In any Bohr orbit of the hydrogen atom, the ratio of kinetic energy to potential energy of the electron is. [MP PET 1994] 1/2 -1/2 2 - 2 20. In the above figure D and E respectively represent. [CPMT 1986, 88] Absorption line of Balmer series and the ionization potential of hydrogen Spectral line of Balmer series and the maximum wavelength of Lyman series Absorption line of Balmer series and the wavelength lesser than lowest of the Lyman series Spectral line of Lyman series and the absorption of greater wavelength of limiting value of Paschen series