2072 Chaitra Regular
2072 Chaitra Regular electrical Engineering Material IOE Pulchowk
1. a) Define Fermi Energy. What is the probability that an
electron having energy less than Fermi energy will occupy an energy level at
absolute zero temperature? Determine the expectation value for any property of
a particle described by a wave function.[8]
b) An electron is confined to an infinite potential well of size 0.1 nm. Calculate the ground energy of the electron and radian frequency. How this electron can be put to the third energy level.[4]
2. a) What is effective mass? The electron at the top of the valence band is said to have negative effective mass. Explain with the help of the E-K diagram.[6]
b) The formation of H2 molecule is more stable than the formation of H3 molecule. Justify with the help of electron energy versus inter-atomic the separation between H-atoms.[6]
3. a) Show that the dielectric loss per unit volume is a function of the frequency of the applied field and the loss tangent.[6]
b) Describe how thermal breakdown and electromechanical breakdown results in a dielectric breakdown in solids.[4]
c) Based on the magnetization vector, explain the diamagnetism, ferromagnetism, and ferromagnetism.[8]
4. a) Explain how strong the magnetic field effects superconductors. Derive the relation of critical current in a superconductor with the necessary diagram.[8]
b) how does band bending occur in semiconductors? Derive Einstein's relationship.[10]
c) If it is desired that the Fermi-level is to be raised to 0.1 eV above intrinsic Fermi-level at room temperature, what type of dopant is to be used? Determine its doping level.[6]
5. a) Present a comparison between Si and GaAs semiconductors with the help of their basic properties and E-k diagram.[6]
b) Derive the expression of a built-in potential and depletion width of a pn junction with necessary diagrams.[8]
b) An electron is confined to an infinite potential well of size 0.1 nm. Calculate the ground energy of the electron and radian frequency. How this electron can be put to the third energy level.[4]
2. a) What is effective mass? The electron at the top of the valence band is said to have negative effective mass. Explain with the help of the E-K diagram.[6]
b) The formation of H2 molecule is more stable than the formation of H3 molecule. Justify with the help of electron energy versus inter-atomic the separation between H-atoms.[6]
3. a) Show that the dielectric loss per unit volume is a function of the frequency of the applied field and the loss tangent.[6]
b) Describe how thermal breakdown and electromechanical breakdown results in a dielectric breakdown in solids.[4]
c) Based on the magnetization vector, explain the diamagnetism, ferromagnetism, and ferromagnetism.[8]
4. a) Explain how strong the magnetic field effects superconductors. Derive the relation of critical current in a superconductor with the necessary diagram.[8]
b) how does band bending occur in semiconductors? Derive Einstein's relationship.[10]
c) If it is desired that the Fermi-level is to be raised to 0.1 eV above intrinsic Fermi-level at room temperature, what type of dopant is to be used? Determine its doping level.[6]
5. a) Present a comparison between Si and GaAs semiconductors with the help of their basic properties and E-k diagram.[6]
b) Derive the expression of a built-in potential and depletion width of a pn junction with necessary diagrams.[8]
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