Class 12 Physics Important Chapter 14 Semiconductor Electronics: Materials, Devices and Simple Circuits

Class 12 Physics Important Chapter 14 Semiconductor Electronics: Materials, Devices and Simple Circuits Solutions English Medium As Per The New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters ASSEB Class 12 Physics Additional Solutions in English and select need one. NCERT Class 12 Physics Additional Solutions Download PDF. HS 2nd Year Physics Important Solutions.

Class 12 Physics Important Chapter 14 Semiconductor Electronics: Materials, Devices and Simple Circuits

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Semiconductor Electronics: Materials, Devices and Simple Circuits

Chapter: 14

IMPORTANT QUESTION AND ANSWER

Answer The Following Questions:

1. Write down the truth table on NAND gate.

Ans: 

2. Give one use of solar cell.

Ans: Use: A solar cell is used to convert solar energy into electrical energy, especially in remote areas where conventional electricity is unavailable (e.g., in calculators, satellites, and street lights).

3. What is Reverse Saturation Current?

Ans: (i) The reverse saturation current is the small current that flows through a diode in reverse bias due to the movement of minority charge carriers.

(ii) It is nearly constant for a given temperature and increases slightly with temperature.

4. ICs can be grouped in two categories. What are they?

Ans: These two categories are based on the type of signal the IC handles:

(i) Linear Integrated Circuits (Linear ICs)

(ii) Digital Integrated Circuits (Digital ICs)

5. Write the full forms of:

(i) LCD.

Ans: Liquid Crystal Display.

(ii) CRT.

Ans: Cathode Ray Tube.

6. What is the range of electrical conductivity if the resistivity lies in the range 10⁻⁵ to 10⁶ Ω⋅m

Ans: The conductivity lies in the range 10⁻⁶ to 10⁵ s/m.

7. Explain the principle of a Light Emitting Diode (LED). State two advantages over incandescent lamps.

Ans: Principle: When an LED is forward biased, electrons recombine with holes and release energy in the form of light (electroluminescence).

Advantages:

(i) More energy efficient (less power consumption).

(ii) Longer lifespan and more durable than incandescent lamps.

8. What is energy band gap of a semiconductor? What range is suitable for solar cells?

Ans: The energy band gap is the energy difference between the valence band and conduction band.

For solar cells, the suitable band gap is between 1.0 eV and 1.8 eV .

9. How will you dope a pure Silicon crystal to obtain a p-type and an n-type semiconductor?

Ans: To obtain an n-type semiconductor, a pure silicon crystal is doped with a pentavalent impurity such as phosphorus or arsenic. These atoms have five valence electrons, and when they replace silicon atoms in the crystal lattice, they donate an extra electron, which becomes free to conduct electricity. Thus, electrons become the majority charge carriers. To obtain a p-type semiconductor, the pure silicon crystal is doped with a trivalent impurity such as boron or aluminium. These atoms have only three valence electrons, creating a hole in the lattice where an electron is absent. This hole behaves as a positive charge carrier, and holes become the majority carriers in the p-type material.

10. Give a comparative discussion on majority and minority carriers in n-type and p-type semiconductors.

Ans: In an n-type semiconductor, electrons are the majority carriers as the material is doped with a pentavalent impurity that contributes extra free electrons. Holes are present in very small quantities and are considered minority carriers. In contrast, a p-type semiconductor is doped with a trivalent impurity, which creates holes in the crystal lattice. These holes act as the majority charge carriers, while electrons, which are fewer in number, are the minority carriers. Thus, the type of doping determines which type of carrier dominates the conduction process.