NCERT Solution Physics Class 12 Chapter 11 Dual Nature of Radiation and Matter
NCERT Solution Physics Class 12 Chapter 11 Dual Nature of Radiation and Matter all questions and answers. Physics Class 12 11th Chapter Dual Nature of Radiation and Matter exercise solution and experts answer. As one of online learning platforms, we (netex.) are excited to offer the NCERT Solution Physics Class 12 Chapter 11. This solution is designed to help students who are looking to brush up on their physics concepts on Chapter 11 Dual Nature of Radiation and Matter.
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11.18.) Show that the wavelength of electromagnetic radiation is equal to the de Broglie wavelength of its quantum (photon).
ANSWER-
We know that for electromagnetic radiation travelled with the speed of light (c) the energy is
From equation 1 and 2 we can conclude that the wavelength of electromagnetic radiation is equal to the de Broglie wavelength of its quantum (photon).
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11.37.) Answer the following questions:
(a) Quarks inside protons and neutrons are thought to carry fractional charges [(+2/3)e ; (–1/3)e]. Why do they not show up in Millikan’s oil-drop experiment?
(b) What is so special about the combination e/m? Why do we not simply talk of e and m separately?
(c) Why should gases be insulators at ordinary pressures and start conducting at very low pressures?
(d) Every metal has a definite work function. Why do all photoelectrons not come out with the same energy if incident radiation is monochromatic? Why is there an energy distribution of photoelectrons?
(e) The energy and momentum of an electron are related to the frequency and wavelength of the associated matter wave by the relations: E = h ν, p =h/ λ But while the value of λ is physically significant, the value of ν (and therefore, the value of the phase speed ν λ) has no physical significance. Why?
ANSWER-
(b) If we consider dynamics of electron in any field magnetic or electrical field we can observe that combine effect of (e/m)is playing major role thane and m separately for justifying this consider the following relations
In electric field when potential V is applied to the electron then its velocity is given by
(c) At atmospheric pressure, the molecules of gases are travelling randomly and collide with each other very frequently so there is very less chance that the ions of gas can reach to the electrons hence; gases are insulators at atmospheric pressure. When pressure decreases, molecules random motion settled up to some extend this increases the chance for the ions to reach electrodes and form a current. Hence conducting the electricity.
(d) The work function of a metal is the minimum energy required for electron to come out of the metal surface. All the electrons have different energy depending upon the shell in which it orbits. When monochromatic light i.e. light of unique wavelength incident on metal, electrons get energy. Electrons spend different energy to come out of the surface. Hence the remaining energy received from incident ray is given to the photon .Hence; these emitted electrons show different energy distributions. The absolute value of energy of a particle is arbitrary within the additive constant hence the value of λ is physically significant, the value of ν (and therefore, the value of the phase speed ν λ) has no physical significance.
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