فيزيائيه صغيرونه
24-10-2009, 18:41
السلام عليكم ورحمه الله وبركاته
الي اخواني واخواتي في منتدي الفيزيائيين العرب
ارجو منكم مساعدتي انا طالبه ماستر في بريطانيا
وبدأت كورسي متاخره ب 6 محاضرات وهذا اول problem sheet ارجوا منكم مساعدتى عليا تسليمه يوم الاثنين
1.2consider acharge e ( the nucleus surrounded by ahomogeneous cloud of charge __e and radius a0 (the electron as aclassical model for an atom.
A_ starting from the Coulomb attraction between Cloud and nucleus, show that for r>a0 a displacement r of the coud leads to alinear restoring force.
(hint: calculate the force the electron cloud exerts on the nucleus, making use of the fact that only the part within r contributes )
B) Calculate the spring constant k and ,using the electron mass m, the resonance frequency w0 of the lorentz oscillator.
c) Compare your result with the transition frequency of the n=1 ___ n=2
transition in hydrogen
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السؤال الثاني
In the lorentz oscillator model < we have neglected the influence of the magnetic field of the light wave on the atom .
Here < you should consider one of its effects
a) sketch the orientation of the vectors E AND B OF the light wave , the velocity v of the electron accelerated by the wave and the direction of the magnetic component of the lorentz force on the electron
b) Find a vector expression for the average value of the magnetic lorentz force on an harmonically bound electron driven by aresonant light field in terms of the amplitude E0 and the damping rate L . use your result to explain the phenomenon of radiation pressure in the lorentz model .
الي اخواني واخواتي في منتدي الفيزيائيين العرب
ارجو منكم مساعدتي انا طالبه ماستر في بريطانيا
وبدأت كورسي متاخره ب 6 محاضرات وهذا اول problem sheet ارجوا منكم مساعدتى عليا تسليمه يوم الاثنين
1.2consider acharge e ( the nucleus surrounded by ahomogeneous cloud of charge __e and radius a0 (the electron as aclassical model for an atom.
A_ starting from the Coulomb attraction between Cloud and nucleus, show that for r>a0 a displacement r of the coud leads to alinear restoring force.
(hint: calculate the force the electron cloud exerts on the nucleus, making use of the fact that only the part within r contributes )
B) Calculate the spring constant k and ,using the electron mass m, the resonance frequency w0 of the lorentz oscillator.
c) Compare your result with the transition frequency of the n=1 ___ n=2
transition in hydrogen
:::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::
السؤال الثاني
In the lorentz oscillator model < we have neglected the influence of the magnetic field of the light wave on the atom .
Here < you should consider one of its effects
a) sketch the orientation of the vectors E AND B OF the light wave , the velocity v of the electron accelerated by the wave and the direction of the magnetic component of the lorentz force on the electron
b) Find a vector expression for the average value of the magnetic lorentz force on an harmonically bound electron driven by aresonant light field in terms of the amplitude E0 and the damping rate L . use your result to explain the phenomenon of radiation pressure in the lorentz model .