Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Write down basic postulates of sommerfield’s free electron gas model. Show that the number of energy states per unit energy is given by g(E) = 4Rv/h3 (2m)3/2 E1/2 . What is the density of energy states in metals? Obtain an expression for the density of states for free electron gas in metals.
Sommerfield's Free Electron Theory
Sommerfeld investigated the behavior of electron gas taking into account the quantum theory and the Pauli's exclusion principle. In Sommerfeld's model the free electrons are assumed to be the valence electrons of the composing atoms. The alkali metals are assumed to contribute one free electron per atom. These electrons are free to move in a constant potential in the metal. They cannot come out of the metal surface, which suggests the presence of high potential barrier supposed to be zero. Thus the conductor acts as a potential well of potential box for the free electrons. To understand this, first we will consider a one-dimensional model and then three-dimensional model of electron gas. According to the free electron model of a solid, all the valence electrons of the constituent atoms of the solid are able to move freely through the volume of the specimen of the solid. These electrons are distinct from those filling the electronic shells of the ion cores. Besides, a s a first approximation it is assumed that those electrons, termed as conduction electrons are unaffected by the periodic fluctuating potential of the ion cores. These electrons therefore, move freely in a region of constant potential and hence their motion can be described by the motion of a free particle in a large box. Where the energy levels lie very close to each other.
Q. Three dc generators are operating in parallel with excitations such that their external characteristics are almost straight lines over the working range with the following pairs
Program Counter (PC) It is a 16 bit register. It is a memory pointer. It stores the memory address of the next byte of the program to be executed. Memory address is of
Each of the following functions is abs(H(jw))^2 of a certain network function H(s). Obtain all the possible H(s) for each given abs(H(jw))^2. [(w^4)+25]/[(w^4)+(12w^2)+49]
What is Capacitance - Capacitance is explained to be the amount of charge Q stored in among the two plates for a potential difference or voltage V existing across the plates.
Q. Counting to moduli other than 2 is a frequent requirement, the most common being to count through the binary-coded decimal (BCD) 8421 sequence. All that is required is a four-st
Q. For a 6-bit weighted-resistor D/A converter, if R is the resistor connected to the MSB, find the other resistor values needed, and calculate the maximum analog output voltage, t
Holography In 1947, Denis Gabor invented a different type of photography, know as holography. He named this new technique wave front construction. According to this technique
What is Commutator? Explain in brief about the Commutator action in dc generator.
Question: a). Draw the energy diagram of a pn junction: (i) at thermal equilibrium, (ii) when a forward bias with magnitude half the built in potential (V = φk/2) is applie
Positive Edge Triggered D Flip Flop In this type of D flip Flop ( 7475) shown in figure the output changes with positive edge of the CLK when CLK changes from 0 to 1
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd