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Physics (Semiconductor Physics)

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2025 1052012025 OLD 105201

2025105201

B.Tech 2nd Semester Examination, 2025 (Old Course)

03 Hours70 marks

Instructions

  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct option/answer the following (Any seven question only):

Ask AI

  1. Q1.1

    Source for Optical fibre communication can be

    a)

    LED

    b)

    Ordinary light

    c)

    LASER

    d)

    Both (i) & (ii)

    Ask AI

  2. Q1.2

    A light emitting diode is

    a)

    Lightly doped

    b)

    Heavily doped

    c)

    Zener Diode

    d)

    Intrinsic Semiconductor

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  3. Q1.3

    What are phonons?

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  4. Q1.4

    Give an example of indirect bandgap semiconductor.

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  5. Q1.5

    Fermi level of Potassium is 2.1 eV. Calculate the speed of electron at Fermi level. (mass of electron $ = 9.1 \times 10^{-31} kg $)

    Ask AI

  6. Q1.6

    Write down any two characteristics of wave function.

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  7. Q1.7

    Write down time-independent Schrödinger's wave equation in 1-dimension.

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  8. Q1.8

    The de Broglie wavelength of a particle moving with a velocity 200 m/s is 14.14 Å. What will be de Broglie wavelength if kinetic energy is doubled?

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  9. Q1.9

    State Heisenberg's uncertainty principle.

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  10. Q1.10

    Define mobility of a charge carrier. Give its S.I. Unit.

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Q.2 Solve both questions :

Ask AI

  1. Q2.1

    Discuss Kronig-Penney model for the motion of an electron in a periodic potential and the existence of allowed and forbidden energy bands.

    Ask AI

  2. Q2.2

    Find out the energy level in Sodium for which the probability of occupation at 300K is 0.50. (Given Fermi energy for Sodium is 3.13 eV. Planck's constant $ = 1.38 \times 10^{-23} $ in S.I. Units)

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Q.3 Solve both questions :

Ask AI

  1. Q3.1

    Discuss the structure and working of semiconductor LASER. Draw and explain its energy band diagram.

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  2. Q3.2

    What is population inversion? What is its importance in Lasing action?

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Q.4 Solve both questions :

Ask AI

  1. Q4.1

    Derive an expression for effective mass of an electron.

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  2. Q4.2

    Explain the significance of negative effective mass.

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Q.5 Write short notes on :

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  1. Q5.1

    Advantages and Disadvantages of solar cell

    Ask AI

  2. Q5.2

    Photodetectors and its application

    Ask AI

Q.6 Solve both questions :

Ask AI

  1. Q6.1

    Derive the expression for the equilibrium concentration of electrons in the conduction band.

    Ask AI

  2. Q6.2

    Explain the effect of temperature on Fermi level.

    Ask AI

Q.7 Write notes on any two of the following:

Ask AI

  1. Q7.1

    Pumping mechanisms in LASER

    Ask AI

  2. Q7.2

    Bloch Theorem

    Ask AI

  3. Q7.3

    Dependence of Fermi energy on carrier concentration

    Ask AI

Q.8 Solve this question :

Ask AI

  1. Q8.1

    What are LEDs? Sketch the relative eye response as a function of wavelength. Describe device structure and materials used for LED with its characteristics.

    Ask AI

Q.9 Solve both questions :

Ask AI

  1. Q9.1

    Discuss the structure, working principle and characteristics of PIN and Avalanche Photodiodes.

    Ask AI

  2. Q9.2

    Explain the effect of temperature on Fermi level.

    Ask AI

2025OLD105201

B.Tech 2nd Semester Examination, 2025 (Old Course)

03 Hours70 marks

Instructions

  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct option/answer the following (Any seven question only):

Ask AI

  1. Q1.1

    Source for Optical fibre communication can be

    a)

    LED

    b)

    Ordinary light

    c)

    LASER

    d)

    Both (i) & (ii)

    Ask AI

  2. Q1.2

    A light emitting diode is

    a)

    Lightly doped

    b)

    Heavily doped

    c)

    Zener Diode

    d)

    Intrinsic Semiconductor

    Ask AI

  3. Q1.3

    What are phonons?

    Ask AI

  4. Q1.4

    Give an example of indirect bandgap semiconductor.

    Ask AI

  5. Q1.5

    Fermi level of Potassium is 2.1 eV. Calculate the speed of electron at Fermi level. (mass of electron $ = 9.1 \times 10^{-31} kg $)

    Ask AI

  6. Q1.6

    Write down any two characteristics of wave function.

    Ask AI

  7. Q1.7

    Write down time-independent Schrödinger's wave equation in 1-dimension.

    Ask AI

  8. Q1.8

    The de Broglie wavelength of a particle moving with a velocity 200 m/s is 14.14 Å. What will be de Broglie wavelength if kinetic energy is doubled?

    Ask AI

  9. Q1.9

    State Heisenberg's uncertainty principle.

    Ask AI

  10. Q1.10

    Define mobility of a charge carrier. Give its S.I. Unit.

    Ask AI

Q.2 Solve both questions :

Ask AI

  1. Q2.1

    Discuss Kronig-Penney model for the motion of an electron in a periodic potential and the existence of allowed and forbidden energy bands.

    Ask AI

  2. Q2.2

    Find out the energy level in Sodium for which the probability of occupation at 300K is 0.50. (Given Fermi energy for Sodium is 3.13 eV. Planck's constant $ = 1.38 \times 10^{-23} $ in S.I. Units)

    Ask AI

Q.3 Solve both questions :

Ask AI

  1. Q3.1

    Discuss the structure and working of semiconductor LASER. Draw and explain its energy band diagram.

    Ask AI

  2. Q3.2

    What is population inversion? What is its importance in Lasing action?

    Ask AI

Q.4 Solve both questions :

Ask AI

  1. Q4.1

    Derive an expression for effective mass of an electron.

    Ask AI

  2. Q4.2

    Explain the significance of negative effective mass.

    Ask AI

Q.5 Write short notes on :

Ask AI

  1. Q5.1

    Advantages and Disadvantages of solar cell

    Ask AI

  2. Q5.2

    Photodetectors and its application

    Ask AI

Q.6 Solve both questions :

Ask AI

  1. Q6.1

    Derive the expression for the equilibrium concentration of electrons in the conduction band.

    Ask AI

  2. Q6.2

    Explain the effect of temperature on Fermi level.

    Ask AI

Q.7 Write notes on any two of the following:

Ask AI

  1. Q7.1

    Pumping mechanisms in LASER

    Ask AI

  2. Q7.2

    Bloch Theorem

    Ask AI

  3. Q7.3

    Dependence of Fermi energy on carrier concentration

    Ask AI

Q.8 Solve this question :

Ask AI

  1. Q8.1

    What are LEDs? Sketch the relative eye response as a function of wavelength. Describe device structure and materials used for LED with its characteristics.

    Ask AI

Q.9 Solve both questions :

Ask AI

  1. Q9.1

    Discuss the structure, working principle and characteristics of PIN and Avalanche Photodiodes.

    Ask AI

  2. Q9.2

    Explain the effect of temperature on Fermi level.

    Ask AI

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