+2 Physics Unit 6 - Atomic Physics

15 Questions

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+2 Physics Unit 6 - Atomic Physics

Prepared by P. ILAIYARAJA M. Sc. ,B. Ed. , PG ASST IN PHYSICS , GHSS, PANCHANATHIKKULAM EAST, NAGAI DT.   ; & www. Padasalai. Net


Questions and Answers
  • 1. 
    The cathode rays are  
    • A. 

      A stream of electrons

    • B. 

      A stream of positive ions

    • C. 

      A stream of uncharged particles

    • D. 

      The same as canal rays

  • 2. 
    A narrow electron beam passes undeviated through an electric field and an overlapping magnetic field . The electron motion, electric field and magnetic field are mutually perpendicular. The speed of the electron is
    • A. 

      (3)

    • B. 

      (1)

    • C. 

      (2)

    • D. 

      (4)

  • 3. 
    According to Bohr’s postulates, which of the following quantities take discrete values?
    • A. 

      Angular momentum

    • B. 

      Kinetic energy

    • C. 

      Potential energy

    • D. 

      Option 4

  • 4. 
    The ratio of the radii of the first three Bohr orbit is,
    • A. 

      1 : 4 : 9

    • B. 

      1 : 8 : 27

    • C. 

      1 : 1/2 : 1/3

    • D. 

      1 : 2 : 3

  • 5. 
    The first excitation potential energy or the minimum energy required to excite the atom from ground state of hydrogen atom is,
    • A. 

      10.2 eV

    • B. 

      13.6 eV

    • C. 

      3.4 eV

    • D. 

      1.89 eV

  • 6. 
    According to Rutherford atom model, the spectral lines emitted by an atom is,
    • A. 

      Continuous spectrum

    • B. 

      Continuous absorption specturm

    • C. 

      line spectrum

    • D. 

      Band spectrum

  • 7. 
    Energy levels A, B, C of a certain atom correspond to increasing values of energy (i.e.,) . If  are the wavelengths of radiations corresponding to the transitions C to B, B to A and C to A respectively, which of the following statements is correct.
    • A. 

      (2)

    • B. 

      (1)

    • C. 

      (3)

    • D. 

      (4)

  • 8. 
    The elliptical orbits of electron in the atom were proposed by
    • A. 

      Sommerfeld

    • B. 

      J.J.Thomson

    • C. 

      Bohr

    • D. 

      De Broglie

  • 9. 
    X−ray is
    • A. 

      Phenomenon of conversion of kinetic energy into radiation.

    • B. 

      Conversion of momentum

    • C. 

      Conversion of energy into mass

    • D. 

      Principle of conservation of charge

  • 10. 
    In an X-ray tube, the intensity of the emitted X−ray beam is increased by
    • A. 

      Increasing the filament current

    • B. 

      Decreasing the filament current

    • C. 

      increasing the target potential

    • D. 

      Decreasing the target potential

  • 11. 
    • A. 

      An atomic transition in the target.

    • B. 

      The kinetic energy of the striking electron

    • C. 

      The kinetic energy of ions of the target

    • D. 

      The kinetic energy of the free electrons of the target

  • 12. 
    A Coolidge tube operates at 24800 V. The maximum frequency of X radiation emitted from Coolidge tube is
    • A. 

      (1)

    • B. 

      (2)

    • C. 

      (3)

    • D. 

      (4)

  • 13. 
    In hydrogen atom, which of the following transitions produce a spectral line of maximum wavelength
    • A. 

      6 → 5

    • B. 

      4 → 1

    • C. 

      2 → 1

    • D. 

      5 → 2

  • 14. 
    In hydrogen atom, which of the following transitions produce a spectral line of maximum frequency
    • A. 

      2 → 1

    • B. 

      6 → 2

    • C. 

      4 → 3

    • D. 

      5 → 2

  • 15. 
    • A. 

      The number of atoms in the excited state is greater than the number of atoms in the ground state.

    • B. 

      The number of atoms in the ground state is equal to the number atoms in the excited state.

    • C. 

      No atoms are available in the excited state.

    • D. 

      The number of atoms in the ground state is greater than the number of atoms in the excited state.