====== Chapter 20: Atomic Spectra ======
This is a twentieth chapter of the book Physics 12 published by Punjab Curriculum and Textbook Board, Lahore, Pakistan.

After studying this chapter, the students will be able to:

  * Know experimental facts of hydrogen spectrum.
  * Describe Bohr's postulates of hydrogen atom.
  * Explain hydrogen atom in terms of energy levels.
  * Describe de-Brogile•s interpretation of Bohr's orbits.
  * Understand excitation and ionization potentials.
  * Describe uncertainty regarding position of electron in the atom.
  * Understand the production, properties and uses of X-rays.
  * Describe the terms spontaneous emission, stimulated emission, metastable state and population inversion.
  * Understand laser principle.
  * Describe the He-Ne gas laser.
  * Describe the application of laser including holography.

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| **Theory**: |{{ :fsc-pctb-12:notes:fsc-pctb-12-theory-ch20.pdf |Download PDF}} |
| **Question**: |{{ :fsc-pctb-12:notes:fsc-pctb-12-questions-ch20.pdf |Download PDF}} |
| **Numerical**: |{{ :fsc-pctb-12:notes:fsc-pctb-12-numericals-ch20.pdf |Download PDF}} |
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{{tag>FSc FSc_Part2 PCTB Notes}}