Assignment Module 01 No. CE 02 Vector Mechanics of Particles

Question.1     Define vector field, Give two examples of each.

Question.2     Define del operator.

Question.3     What do you mean by gradient of scalar field?

Question.4     Define the divergence of a vector field.

Question.5     Define the curl of vector field.

Question.6     What do you meant by Solenoidal vector field?

Question.7     What do you meant by irrotational vector field?

Question.8     Define field. State two types of field.

Question.9     Under what conditions the vector field is solenoidal and irrotational?.

Question.10   State the physical meaning of grad f.

Question.11   State the values of position vector r and r.

Question.12   State the three fundamental operations with ∇ which are of physical interest.

Question.13   Define rotational vector Field.

Question.14   What do you meant by directional derivative.

 

Fermi function or Fermi dirac didtribution funtion

 

Fermi function or Fermi Dirac distribution function

The probability that a particular quantum state of energy E of fermions is occupied at a particular temperature T is given by a function f (E) and is called Fermi function. 

Let a system of electrons is in thermal equilibrium at a temperature T kelvin. 

The probability f(E) of an electron occupying a particular energy level E is given by

 

 

Where f (E) is Fermi function

E_F is called Fermi energy

K is Boltzmann constant
K = 1.38 × 10 ⁻²³ J/K

Value of Boltzmann constant in eV  is K = 8.62 × 10 ⁻⁵ eV/K

T is absolute temperature

For a filled energy level f (E) = 1

For an unfilled energy level f (E) = 0

Fermi function is obeyed by Fermions

Fermions are half integer spin particles.  Example : electrons which obey Pauli’s Exclusion principle.

Application of Fermi function or Fermi Dirac distribution function

 

 

Important Formula

 

Questions

1. what is fermi funtion or fermi dirac distribution function ?
2. What is Fermi level?
3. What is Fermi energy?  
4. Define Fermi velocity.
   
5. Explain thermal equilibrium in in semiconductors.
6. write the equation for the Fermi level energy in n – type semiconductor.    
7. What is Fermi’s golden rule?
8. Discuss in detail the dependence of Fermi level on carrier concentration and temperature.
9. What do you mean by occupation probability?
10. Write the expression for the Fermi level energy in n – type semiconductor.

Numerical Problems

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Assignment Questions : Physics : Semiconductors : Module 01 : Branch CSE & EE

 

 Assignment Questions

Semiconductors

1.    What are semiconductors?

2.    What are the types of Semiconductor?

3.    What are conductors? Give two examples Semiconductors?

4.    Give examples?

5.    What are insulators? Give two examples?

6.    What is intrinsic semiconductor?

7.    What is an extrinsic semiconductor?

8.    At what temperature would an intrinsic semiconductor behave like a perfect insulator?

9.    Distinguish between n-type and p-type semiconductors

10. Draw relevant energy level diagrams of n-type and p-type semiconductors

11. What is a hole?

12. Name the charge carriers in the following at room temperature: (i) conductor (ii) semiconductor

13. Name the majority charge carriers in p-type semiconductors.

14. Differentiate between intrinsic and extrinsic semiconductors with examples.

15. Name the factors on which electrical conductivity of a pure semiconductor depends at a given temperature.

16. Differentiate between conductor, semiconductor and insulator with suitable examples.

17. What is negative temperature coefficient of resistance?

18. How does the conductivity of a semiconductor change with rise in its temperature?

19. Write the properties of semiconductors.

20. Differentiate between Elemental semiconductors and Compound semiconductors

21. Explain direct bandgap semiconductor and indirect bandgap semiconductor

22. Differentiate between direct bandgap semiconductor and indirect bandgap semiconductor.

23. What is the basic difference between metal and semiconductor?

 

Doping

 

1.    What is doping?

1.    Name one dopant which can be used with germanium to form an n-type semiconductor.

2.    What are dopants?

3.    What are pentavalent and trivalent impurities or dopants

 

Carrier Generation and Recombination

1.    Define Carrier Generation.

2.    Define Carrier Recombination.

3.    Write differences between Carrier Generation and Recombination

4.    What is trap in semiconductor?

Diffusion  and drift

1.    Define drift and drift current in semiconductors.

2.    Define diffusion and diffusion current in semiconductors.

3.    What is diffusion length.

4.    Differentiate between drift and diffusion currents.

5.    Explain carrier transport in semiconductors.

6.    What is drift and diffusion current in semiconductor?

7.   What is the drift voltage?

8.   What does the diffusion coefficient mean?

9.    Give the expression for drift current density µ due to electron.

10. write the equation for drift current density due to holes.

11. write the equation for diffusion current density due to electron.

12. write the expression for diffusion current density due to holes.

13. Explain Fick's Law

Fermi energy

1.    What is Fermi level?

2.    What is Fermi energy?

3.    Explain thermal equilibrium in in semiconductors.

4.    write the equation for the Fermi level energy in n – type semiconductor.    

5.   What is Fermi’s golden rule?

6.    Discuss in detail the dependence of Fermi level on carrier concentration and temperature.

7.    What do you mean by occupation probability?

8.    Write the expression for the Fermi level energy in n – type semiconductor.