Class name Subject Book title Chapter number Content Created at
Class XII Physics Physics Part-II 3 energy of the emitted photoelectrons increases linearly with the frequency of the incident radiation, but is independent of its intensity (Fig. 11....
Class XII Physics Physics Part-II 3 end ofsection 11.4.3. Further, we should note that in the wave picture, the absorption of energy by electron takes place continuously over the enti...
Class XII Physics Physics Part-II 3 (11.2) is known as Einstein’s photoelectric equation. We now see how this equation accounts in a simple and elegant manner all the observations on ...
Class XII Physics Physics Part-II 3 number of electrons coming out of a convincing evidence of the metal (for > ). This explains why, for > , the atomic picture of matter. 0 0 The thi...
Class XII Physics Physics Part-II 3 During 1906-1916, Millikan performedaseriesofexperimentsonphotoelectriceffect,aimedatdisproving Einstein’s photoelectric equation. He measured the ...
Class XII Physics Physics Part-II 3 summarise the photon picture of electromagnetic radiation as follows: (i) In interaction of radiation with matter, radiation behaves as if it is ma...
Class XII Physics Physics Part-II 3 A E 3.98×10 J X 15 E = 5.0 10 photons per second. Example 11.2 The work function of caesium is 2.14 eV. Find (a) the threshold frequency for caesiu...
Class XII Physics Physics Part-II 3 seeing an object by our eye, both descriptions are 1 – important. The gathering and focussing mechanism of 2 light by the eye-lens is well describe...
Class XII Physics Physics Part-II 4 theoretical prediction based on the assumption that the target atom has a small, dense, positively charged nucleus. Many of the a-particles pass th...
Class XII Physics Physics Part-II 3 material particle is basically a hypothesis whose validity can be tested only by experiment. However, it is interesting to see that it is satisfied...
Class XII Physics Physics Part-II 3 speed v ’ = 30.0 m/s. Then momentum p’ = m’ v’ = 0.150 (kg) 30.0 (m/s) p’= 4.50 kg m/s de Broglie wavelength ’ = h/p’ –34 . = 6.63×10 Js 1 4 .0 × k...
Class XII Physics Physics Part-II 3 , characteristic of the metal, no photoelectric emission takes place, no matter how large the intensity may be. 6. The classical wave theory could ...
Class XII Physics Physics Part-II 3 The waves associated with the moving material particles are called matter waves or de Broglie waves. 9. The de Broglie wavelength ( ) associated wi...
Class XII Physics Physics Part-II 3 has to do with the fact that electrons obey Pauli’s exclusion principle. 3. Because of the energy distribution of free electrons in a metal, the en...
Class XII Physics Physics Part-II 3 mW. (a) Find the energy and momentum of each photon in the light beam, (b) How many photons per second, on the average, arrive at a target irradiat...
Class XII Physics Physics Part-II 3 m/s? 11.11 Show that the wavelength of electromagnetic radiation is equal to the de Broglie wavelength of its quantum (photon). Reprint 2026-27
Class XII Physics Physics Part-II 4 Physics Chapter Twelve ATOMS 12.1 I NTRODUCTION By the nineteenth century, enough evidence had accumulated in favour of through gases carried out b...
Class XII Physics Physics Part-II 4 R internal structure of an atom and the spectrum of British physicist who did N radiation emitted by it. In 1885, Johann Jakob Balmer T (1825 – 189...
Class XII Physics Physics Part-II 4 atom as simple as hydrogen, consisting of a single electron and a single proton, emit a complex spectrum of specific wavelengths? In the classical ...
Class XII Physics Physics Part-II 4 most of an atom is empty space. With the atom being largely empty space, it is easy to see why most α-particles go right through a thin metal foil....
Class XII Physics Physics Part-II 4 impact parameter, b of collision. The impact parameter is the perpendicular distance of the initial velocity vector of the a-particle from the cent...
Class XII Physics Physics Part-II 4 of the radius of electron’s orbit to the radius of nucleus is (1010m)/(10 –15m) = 10 , that is, the radius of the electron’s orbit is 10 times larg...
Class XII Physics Physics Part-II 4 0 d 0 Thus the distance of closest approach d is given by 2Ze2 d = 4π ε0 The maximum kinetic –12rgy found in a-particles o9 natu2al 2rigin is 7.7 M...
Class XII Physics Physics Part-II 4 = 2 (12.3) 4πε0mv The kinetic energy (K) and electrostatic potential energy (U) of the electron in hydrogen atom are 1 2 e2 e2 K = mv = and U = − 2...
Class XII Physics Physics Part-II 4 wavelengths 296 only. A spectrum of this kind is termed as emission line spectrum and it Reprint 2026-27 Atoms consists of bright lines on a dark b...