Chapter 14: Semiconductors for AHSEC Class 12 Physics

Here are some probable questions from Chapter 14: Semiconductors for AHSEC Class 12 Physics, based on recent trends and previous years' papers:

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Short Answer Type (1-2 Marks)

1. Define energy band and energy gap in a solid.
2. What is a semiconductor? Give two examples.
3. Differentiate between intrinsic and extrinsic semiconductors.
4. What is doping? Why is it necessary for semiconductors?
5. What is the difference between p-type and n-type semiconductors?
6. What is a depletion layer in a p-n junction?
7. Define knee voltage in a p-n junction diode.
8. What is rectification? How does a diode act as a rectifier?
9. Write two differences between conductors, semiconductors, and insulators.
10. What is meant by drift current and diffusion current in a semiconductor?

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Short Derivation/Numerical Type (3-4 Marks)

11. Explain the formation of the depletion region in a p-n junction diode.
12. Draw and explain the V-I characteristics of a p-n junction diode in forward and reverse bias.
13. Explain the working of a full-wave rectifier with a circuit diagram.
14. Explain how a transistor can be used as an amplifier.
15. What is a Zener diode? Explain its use as a voltage regulator.
16. Derive an expression for the conductivity of a semiconductor in terms of charge carrier concentration.
17. Draw and explain the circuit diagram of a common-emitter amplifier.
18. Explain how light-emitting diodes (LEDs) work.
19. Calculate the current flowing through a diode when a 0.7V forward voltage is applied across a silicon p-n junction.
20. In an n-type semiconductor, the electron concentration is 5 × 10¹⁶ cm⁻³ at 300K. If the intrinsic carrier concentration is 1.5 × 10¹⁰ cm⁻³, calculate the hole concentration.

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Long Answer Type (5-6 Marks)

21. Explain the energy band theory of solids and classify materials into conductors, semiconductors, and insulators based on it.
22. With a neat diagram, explain the working of a photodiode.
23. Explain the working principle of a solar cell.
24. What are logic gates? Explain AND, OR, and NOT gates with truth tables and logic circuit diagrams.
25. Describe the working of a common-base transistor amplifier with a circuit diagram.