CBSE Physics Semi-Conductor Devices Expected Questions : Unit XI
Long Answer Questions (5-Marks Questions)
1. Explain action of a transistor as an amplifier.
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2. Explain with the help of a labelled circuit diagram how a common emitter n-p-n transistor can be used as an amplifier. Derive an expression for its voltage gain.
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3. Explain how an intrinsic semiconduct.or can be converted into (i) n-type ; (ii) /j-type semi¬conductor. Give one example of each and their energy band diagrams.
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4. What is the functional” an emitter, base and collector in a transistor ? Explain with the help of a circuit diagram, the use of NPN transister in common base configuration.
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5. Explain with examples the formation of energy bands in solids. For an extrinsic semiconductor, mark the donor and aceptor levels in the energy band diagram.
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6. What is n-p-n transistor ? How does it differ from p-n-p transistor ? Give their symbols. Explain the transistor action.
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7. Briefly explain the working of a NOT gate using transistor.
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8. Explain the variation of resistivity with temperature in semiconductors.
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