EC1201 Electron Devices B.E Question Bank : niceindia.com
Name of the College : Noorul Islam College of Engineering
University : Anna University
Degree : B.E
Department : Electronics and Communication Engineering
Subject Code/Name : EC 1201 – Electron Devices
Year : II
Semester : III
Document Type : Question Bank
Website : niceindia.com
Download :https://www.pdfquestion.in/uploads/ni…on_Devices.pdf
NICE Electron Devices Question Paper
Chapter 1 – Electron Ballistics And Intrinsic Semiconductors :
Part A :
1. Give the value of Charge, Mass of an electron :
Charge of an electron – 1.6 x 10 -19 coloumbs Mass of an electron – 9.11 x 10 -31 Kgs\
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2. Define Potential :
A potential of V volts at point B with respect to point A, is defined as the work done in taking unit positive charge from A to B , against the electric field.
3. Give the expression for Equation of motion :
Y = e x x t2/ 2m
4. What is Transit time? : Give the expression for it:
It is the time taken by the electron to travel a distance‘d’ between the plates.
5. What is the Force experienced by an electron in Magnetic field? :
Fm = B x e x V Newton’s
6. Define Current density :
It is defined as the current per unit area of the conducting medium.
J = I / A
7. Define Electron volts :
If an electron falls through a potential of one volt then its energy is 1 electron volt.
1 eV = 1.6 x 10 -19 joules
8. What is Electrostatic deflection sensitivity? :
Electrostatic deflection sensitivity of a pair of deflecting plates of a cathode ray oscilloscope ( CRO) is defined as the amount of deflection of electron spot produced when a voltage of 1 Volt DC is applied between the corresponding plates.
9. Give the expression for Electrostatic deflection sensitivity? :
SE = l x D \ 2 x S x Va where l – length of the plates , D – distance between the centre of the plate and screen , S – distance between the plates , Va – anode potential.
10. What is Cyclotron? :
Cyclotron is a device that imparts very high energies to positive ions. These higher energy positive ions are then allowed to bombard some substances, which become radioactive and generally disintegrate.
11. Give the expression for frequency of Cyclotron? :
f = e x B / 2 x x m Hz
12. What is Magnetic deflection sensitivity? :
Magnetic deflection sensitivity of a cathode ray oscilloscope (CRO) is defined as the amount of deflection of electron spot produced when a magnetic flux density of 1 Wb/m2 is applied.
SM = (e / m )1\2 x 1\ (2V0) 1\2 x l x L
13. What is atomic number? :
The number of protons or electrons in an atom is atomic number.
14. What is the relation for the maximum number of electrons in each shell? :
Ans : 2n2
15. What are valence electrons? :
Electron in the outermost shell of an atom is called valence electron.
16. What is forbidden energy gap? :
The space between the valence and conduction band is said to be forbidden energy gap.
17. What are conductors? : Give examples?:
Conductors are materials in which the valence and conduction band overlap each other so there is a swift movement of electrons which leads to conduction. Ex. Copper, silver.
18. What are insulators? : Give examples?:
Insulators are materials in which the valence and conduction band are far away from each other. So no movement of free electrons and thus no conduction. Ex glass, plastic.
19. Give the energy band structure of Insulator :
In Insulators there is a wide forbidden energy gap. So movement of valence electron from valence to conduction band is not possible.
20. Give the energy band structure of Semi conductor :
In Semiconductors there is a small forbidden energy gap. So movement of valence electron from valence to conduction band is possible if the valence electrons are supplied with some energy.