2nd Year Physics Chapter 20 Notes

• Important 2nd year physics chapter 20 mcqs for Intermediate part-II students.
• Atomic spectra
• Atomic spectrum of hydrogen
• Bohr's Model of the Hydrogen atom
• Quantized radii, quantized energy, hydrogen emission spectrum
• Important 2nd year physics chapter 20 important long questions for Intermediate part-II students.
• Inner shell transitions and characteristics X-rays
• Production of X-rays
• The continuous X-ray spectrum
• properties and uses of X-rays 
• Important 2nd year physics chapter 20 exercise short questions for Intermediate part-II students.
• CAT -Scanner
• biological effects of X-rays
• uncertainty with the atom
• spontaneous and stimulated emissions
• Important 2nd year physics chapter 20 numericals for Intermediate part-II students.
• population inversion and Laser action
• Helium-neon laser
• Uses of laser in medicine and industry
• 1. Know experimental facts of hydrogen spectrum.
• Important 2nd year physics chapter 20 notes pdf for Intermediate part-II students.
• 2. Describe Bohr's postulates of hydrogen atom.
• 3. Explain hydrogen atom in terms of energy levels.
• 4. Describe de-Brogile’s interpretation of Bohr's orbits.
• Important 2nd year physics chapter 20 important questions for Intermediate part-II students.
• 5. Understand excitation and ionization potentials.
• 6. Describe uncertainty regarding position of electron in the atom.
• 7. Understand the production, properties and uses of X-rays.
• Important 2nd year physics chapter 20 important short questions for Intermediate part-II students.
• 8. Describe the terms spontaneous emission, stimulated emission, metastable states and population inversion.
• 9. Understand laser principle.
• 10 Describe the He-Ne gas laser.
• 11. Describe the application of laser including holography.
• Important 2nd year physics chapter 20 conceptual questions for Intermediate part-II students.
• The branch of physics that deals with the investigation of wavelengths and intensities of electromagnetic radiation emitted or absorbed by atoms is called spectroscopy. It includes the study of spectra produced by atoms. In general there are three types of spectra called (i) continuous spectra, (ii) band spectra, and (in) discrete or line spectra. Black body radiation spectrum, as described in chapter 19 is an example of continuous spectra: molecular spectra are the examples of band spectra while the atomic spectra, which we investigate in detail in this chapter, are examples of discrete or line spectra.
• Important 2nd year physics chapter 20 solved exercise for Intermediate part-II students.
• Atomic spectra: When an atomic gas or vapour at much less than atmospheric pressure is suitably excited, usually by passing an electric current through it. the emitted radiation has a spectrum, which contains certain specific wavelengths only. An idealized arrangement for observing such atomic spectra. Actual spectrometer uses diffraction grating for better results.
• Important 2nd year physics chapter 20 exercise for Intermediate part-II students.
• The impression on the screen is in the form of lines if the slit in front of the source S is narrow rectangle. It is for this reason that the spectrum is referred to as line spectrum. The fact that the spectrum of any element contains wavelengths that exhibit definite regularities was utilized in the second ha If of the 19th century in identifying different elements.
• These regularities were classified into certain groups called the spectral series. The first such series was identified by J.J Balmer in 1885 in the spectrum of hydrogen. This series, called the Balmer series. and is in the visible region of the electromagnetic spectrum.
• Important 2nd year physics chapter 20 solved numericals for Intermediate part-II students.
• The results obtained by Balmer were expressed in 1896 by J.R Rydberg in the following mathematical form  1 / λ = RH [ 1 / 2^2  -  1 / n^2 ] , where RH is the R dberg's constant. Its value is 1.0974 x 1 0 'm ’. Since then many more series have been discovered and proved helpful in predicting the arrangement of the electrons in different atoms.