12th Class Physics Chapter 19 Notes

Important Easy to understand Notes of Physics of 12th Class Physics Chapter 19 Notes written by Professor Mr. Asad Abbas Suib. These notes are very helpful in the preparation of 12th Class Physics Chapter 19 Notes for students of the 12th class and these are according to the paper patterns of all Punjab Book Boards.

Summary and Contents:
Topics which are discussed in the notes are given below:
  • Important 12th Class physics chapter 19 objective for Intermediate part-II students.
  • What is modern physics?
  • Write the Phenomenon’s which could not explain by the laws of classical physics?
  • What is Frame of reference? Define inertial and non-inertial frame of reference.
  • Important 12th class physics chapter 19 notes pdf for Intermediate part-II students.
  • What is general and Special Theory Of Relativity? Write the postulates of STR.
  • Theory of relativity
  • General theory of relativity
  • Special theory of relativity
  • Important 12th class physics chapter 19 important questions for Intermediate part-II students.
  • Postulates of special theory of relativity
  • Explain the Results of special theory of relativity
  • Proper time and relativistic time
  • Important 12th class physics chapter 19 question answer for Intermediate part-II students.
  • Proper length and relativistic length
  • Definition of Thermal radiations
  • Black body radiations
  • Important 12th physics chapter 19 notes for Intermediate part-II students.
  • Explain Intensity distribution diagram facts.
  • Facts/Results of energy distribution curves
  • Explain plank’s assumption about nature of radiations.
  • Important 12th class physics chapter 19 exercise for Intermediate part-II students.
  • What is photo electric effect, stopping potential and threshold frequency.
  • Important experimental results of photoelectric effect
  • Give the Einstein photo electric effect explanation.
  • Important 12th class physics chapter 19 exercise solutions for Intermediate part-II students.
  • What is Photo cell? Write its uses.
  • What is COMPTON EFFECT? Explain Compton shift formula. 
  • What is Pair production? 
  • What is annilation of matter?
  • Important 12th physics chapter 19 numericals for Intermediate part-II students.
  • What is de-Broglie hypothesis about Wave Nature of Particle?
  • Describe Davisson and Germer experiment.
  • Write a note on electron microscope. 
  • State and explain heisenberg uncertainty principle.
  • What are the measurements on which two observers in relative motion will always agree upon?
  • Since mass is a form of energy, can we conclude that a compressed spring has more mass than the same spring when it is not compressed?
  • As a solid is heated and begins to glow, why does it first appear red?
  • A beam of red light and a beam of blue light have exactly the same energy. Which beam contains the greater number of photons?
  • Which photon, red, green, or blue carries the most (a) energy and (b) momentum?
  • Which has the lower energy quanta? Radio-waves or X-rays?
  • When ultraviolet light falls on certain dyes. Visible light is emitted. Why does this not happen when infrared light falls on these dyes?
  • Will bright light eject more electrons from a metal surface than dimmer light of the same color?
  • When light shines on a surface, is momentum transferred to the metal surface?
  • Why can red light be used in a photographic dark room when developing films, but a blue or white light cannot?
  • Why don’t we observe a Compton Effect with visible light?
  • Can pair production take place in vacuum? Explain.
  • Is it possible to create a single electron from energy? Explain.
  • If electrons behaved only like particles, what pattern would you expect on the screen after the electrons passes through the double slit?
  • If an electron and a proton have the same de Broglie wavelength, which particle has greater speed?
  • We do not notice the de Broglie wavelength for a pitched cricket ball. Explain why?
  • If the following particles have the same energy, which has the shortest wavelength? Electron, alpha particle, neutron, proton.
  • When does light behave as a wave as a particle?
  • What advantages an electron microscope has over an optical microscope?
  • A particle called the pion lives on the average only about 2.6 x 10^-8 s when at rest in the laboratory. It then changes to another form. How long would such a particle live when shooting through the space at 0.95c?
  • What is the mass of a 70 kg man in a space rocket traveling at 0.8c from us as measured from Earth?
  • Yellow light of 577 nm wavelength is incident on a cesium surface. The stopping voltage is found to be 0.25V. Find (a) The Maximum K.E. of the photoelectrons (b) The work function of cesium
  • What is the maximum wavelength of the two photons produced when a positron annihilates an electron? The rest mass energy of each is 0.51 MeV.
  • What is the de Broglie wavelength of an electron whose kinetic energy is 120 eV? 
  • An electron is placed in a box about the size of an atom that is about 1.0 x 10^-10 m. What is the velocity of the electron? 

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