2075 Chaitra Regular
2075 Chaitra Regular electrical Engineering Material IOE Pulchowk
1. Starting from the suitable equation, prove that the
energy of an electron that is confined in an infinite potential well of width L
is quantized. [8]
2. An electron is confined in an infinite potential well of size 0.1nm. Calculate the ground energy of the electron and radian frequency. How can this electron be put to the third energy level?[4]
3. Derive Einstein's relation between mobility and diffusion co-efficient.and also define the term electron mobility, conductivity, and resistivity.[8]
4. Explain the concept of effective mass in crystal with the necessary mathematical expression.[6]
5. Define polarization. Derive the Clausius-Masotti equation showing the relation between relative permittivity and electronic polarizability.[8]
6. Describe how thermal breakdown and electromechanical breakdown results in an electric breakdown in solids.[4]
7. Justify the magnetic material based on magnetization and explain each of them briefly.[8]
8. Explain how strong Magnetic field effects superconductor.[4]
9. Describe the phenomenon of the generation of electrons and holes and conduction in a semiconductor. Also derive an equation for conductivity.[6]
10. How band bending occurs in semiconductors? Derive Einstein's relationship.[10]
11. Pn junction semiconductor has a resistivity of 50-ohm cm. If the mobility of holes is 450 m/Vs, and electron, mobility is three times the mobility of holes at room temperature, find
1.Built-in potential
2.Depletion width that lies in n-region and region respectively
3.The built-in electric field at x=0.[6]
12. Calculate the resistance of pure silicon cubic crystal of 1cm at room temperature. What will be the resistance of the cube when it is dopped with 1 Arsenic in 10^9 silicon atoms and 1 boron atom per billion silicon atoms? Atomic concentration of silicon 0"cm, n-1.45*10 cm?. [8]
2. An electron is confined in an infinite potential well of size 0.1nm. Calculate the ground energy of the electron and radian frequency. How can this electron be put to the third energy level?[4]
3. Derive Einstein's relation between mobility and diffusion co-efficient.and also define the term electron mobility, conductivity, and resistivity.[8]
4. Explain the concept of effective mass in crystal with the necessary mathematical expression.[6]
5. Define polarization. Derive the Clausius-Masotti equation showing the relation between relative permittivity and electronic polarizability.[8]
6. Describe how thermal breakdown and electromechanical breakdown results in an electric breakdown in solids.[4]
7. Justify the magnetic material based on magnetization and explain each of them briefly.[8]
8. Explain how strong Magnetic field effects superconductor.[4]
9. Describe the phenomenon of the generation of electrons and holes and conduction in a semiconductor. Also derive an equation for conductivity.[6]
10. How band bending occurs in semiconductors? Derive Einstein's relationship.[10]
11. Pn junction semiconductor has a resistivity of 50-ohm cm. If the mobility of holes is 450 m/Vs, and electron, mobility is three times the mobility of holes at room temperature, find
1.Built-in potential
2.Depletion width that lies in n-region and region respectively
3.The built-in electric field at x=0.[6]
12. Calculate the resistance of pure silicon cubic crystal of 1cm at room temperature. What will be the resistance of the cube when it is dopped with 1 Arsenic in 10^9 silicon atoms and 1 boron atom per billion silicon atoms? Atomic concentration of silicon 0"cm, n-1.45*10 cm?. [8]
