Pearson mastering physics series#

In principle, how many spectral lines are there inany given series of hydrogen? Explain. Therefore, its radiation is distributed as a continuous distribution.įind the wavelength of the Balmer series spectra! line corresponding to n = 15. Therefore the radiation is the black body radiation from a hot object. As the glass tube of a neon sign contains a low – pressure gas we expect that the light from the sign to be in the form of a line spectrum.ī) But in incandescent bulb the light is emitted by the burning of the filament. Find the distance of closest approachbetween the alpha particle and the gold nucleus for the case K = 3.0 MeV.ĭo yon expect the light given off by (a) a neon sign or (b) an Incandescent lightbulb to be continuous in distribution, or in the form of a line spectrum? Explain.Ī) A neon sign is obtained when neon gas under a low pressure is applied with high voltage. The alpha particle will come to rest when all its initialkinetic energy has been converted to electrical potential energy. Consider an alpha particle with an initial kinetic energy K heading directly for the nucleus of a gold atom (charge = +79e). In Rutherford’s scattering experiments, alpha particles (charge = +2e) were fired at a gold foil. This result led to the idea that there must be a great concentration of positive charge and mass within an atom. When conducting the experiment of α-particle scattering, surprisingly he observed few particles turned back towards source itself. What observation led Rutherford to propose that atoms have a small nucleus containing most of the atom’s mass? If the coppernucleus is a sphere with a diameter of 4.8 × 10−15 m, find the work required to bring an alpha particle (charge = +2e) from rest at infinity to the “surface” of the nucleus. This is one example out of several that Bohr model disagrees with the quantum mechanical model of hydrogen atoms.Ĭopper atoms have 29 protons in their nuclei. So the electrons need not to be equidistant from the centre of the atom even though they are in the same state ‘n’. When there are some electrons in a state ‘n’ then all these electrons are equidistant from the centre of the atom.īut in quantum theory, we have sub levels and sub – sub levels of an electron. At what typical distance from the center of the baseball would you expect to find the electron?Ĭite one example of how the Bohr model disagrees with the quantum mechanical model of the hydrogen atom.Īccording to Bohr’s theory we have only energy level for an electron. Referring to Problem 1, suppose the nucleus of the hydrogen atom were enlarged to the size of a baseball (diameter = 7.3 cm). Due to this reason Rutherford solar system model does not agree with experimental observation. This is in contradiction with the practical observations which shows atoms are stable. Such a revolving electron will lose its energy continuously and it falls into the nucleus after a certain instant of time. Give a reason why the Rutherford solar-system model does not agree with experimental observations.Īccording to Rutherford atomic model, electrons revolve round the nucleus in circular orbits. assume the hydrogenatom to be a sphere of radius 5.3 × 10−11 m, what fraction of its volume is occupied by the nucleus? The electron in a hydrogen atom is typically found at a distance of about 5.3 × 10−11 m from the nucleus, which has a diameter of about 1.0 × 10−15 m. Give areason why the Thomson plum-pudding model does not agree with experimental observations.Įxperimental observations that Thomson plum – pudding model does not agree.ġ) Thomson observed only one spectral line by his assumption while experimental observation reveals that hydrogen spectrum consists of five different series with several lines in each series.Ģ) This model could not provide any satisfactory mechanism for explaining the large deflection suffered by – particles in Rather-ford’s experiment. Mastering Physics Solutions Chapter 31 Atomic Physics