Class 12 Physics chapter 20 notes

Important Easy to understand Notes of Physics of Class 12 Physics chapter 20 notes written by Professor Mr. Asad Abbas Suib. These notes are very helpful in the preparation of Class 12 Physics chapter 20 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 Class 12 Physics chapter 20 mcqs for Intermediate part-II students.
  • What is Spectroscopy?
  • Define the Types of spectra?
  • Definition of Continuous spectrum with example
  • Important Class 12 Physics chapter 20 numericals for Intermediate part-II students.
  • Black body radiation spectrum
  • What is Band spectrum
  • Definition of Line or discrete spectrum with example
  • Important Class 12 Physics chapter 20 exercise questions for Intermediate part-II students.
  • Explain postulates of Bohr Model Of Hydrogen Atom and de-Broglie interpretation of Bohr postulate.
  • De-Broglie interpretation of Bohr Postulate
  • Write General formula for radius, velocity and energy of hydrogen atom
  • Important Class 12 Physics chapter 20 Important numericals for Intermediate part-II students.
  • Define Ground state?
  • Define Excited state?
  • Define Excitation potential?
  • Important Class 12 Physics chapter 20 important questions with answers for Intermediate part-II students.
  • Define of Ionization? 
  • Define Ionization energy?
  • Write formula for Rydberg constant and value
  • What are X-rays? Explain production of X-rays?
  • Important Class 12 Physics chapter 20 notes handwritten for Intermediate part-II students.
  • Why electron cannot exist inside the nucleus?
  • What is laser? Explain its principle and working.
  • Kinds of transitions occurs during the process of laser
  • Important 12 class physics chapter 20 exercise for Intermediate part-II students.
  • Life time for excited and metastable state
  • What is he-ne laser? Write its uses.
  • Uses of He-Ne laser
  • Population inversion occur in neon
  • Important 12 class physics chapter 20 notes for Intermediate part-II students.
  • WHAT IS Holography?
  • Difference b/w orbital and free electrons.
  • Bohr’s theory of hydrogen atom is based upon several assumptions. Do any of these postulate contradict classical physics?
  • Important 12 class physics chapter 20 numerical for Intermediate part-II students.
  • What is meant by a line spectrum? Explain, how line spectrum can be used for the identification of elements?
  • Can the electron in the ground state of hydrogen absorb a photon of energy 13.6 eV and greater than 13.6 eV?
  • How can the spectrum of hydrogen contain so many lines when hydrogen contains one electron?
  • Important ch 2 physics class 20 Notes for Intermediate part-II students.
  • Is energy conserved when an atom emits a photon of light?
  •  Explain why a glowing gas gives only certain wavelengths of light and why that gas is capable of absorbing the same wavelengths? Give a reason why it is transparent to other wavelengths?
  • What do we mean when we say that the atom is excited?
  • Important ch 2 physics class 20 mcqs for Intermediate part-II students.
  • Can X-rays be reflected, refracted, diffracted and polarized just like any other waves? Explain.
  • What are the advantages of lasers over ordinary light?
  • Explain why laser action could not occur without population inversion between atomic.
  • Important ch 2 physics class 20 solutions for Intermediate part-II students.
  • Bohr's model of the hydrogen atom:In order to explain the empirical results obtained by Rydberg. Neils Bohr, in 1913. formulated a model of hydrogen atom utilizing classical physics and Planck's quantum theory This semi classical theory is based on the following three  postulates:
  • Important ch 2 physics class 20 Important solutions for Intermediate part-II students.
  • Postulate I: An electron, bound to the nucleus in an atom, can move around the nucleus in certain circular orbits without radiating. These obits are called the discrete stationary states atom.
  • Postulate Il: Only those stationary orbits are allowed for which orbital angular momentum is equal to an integral multiple of  h / 2π  i.e.,   m v r = nh / 2π , where n - 1, 2, 3..... and n is called the principal quantum number, m and v are the mass and velocity of the orbiting electron respectively, and h is Planck's constant.
  • Important ch 2 physics class 20 numerical for Intermediate part-II students.
  • Postulate III: Whenever an electron makes a transition, that is, jumps from high energy state E, a photon of energy state hf is emitted so that  hf = E - E0 , where f = c / λ is the frequency of the radiation emitted.
  • Important Class 12 Physics chapter 20 short questions and answers for Intermediate part-II students.
  • Which is the energy required to completely remove an electron from the first Bohr orbit. This is called ionization energy. The ionization energy may be provided to the electron by collision with an external electron. The minimum potential through which this external electron should be accelerated so that it can supply the requisite ionization energy is known as ionization potential. Thus for n = 1, 2, 3....... we get the allowed energy levels of a hydrogen atom to be

Loading your document...

Download PDF