Q1 Draw separate energy-level bands for conductors, semiconductors and insulators and label each of them to illustrate the behaviour of (i) a conductor, (ii) a pure semiconductor and (iii) an insulator. Solution

Q2 Explain formation of energy bands in solids. Distinguish between conductors (metals), insulators and semiconductors on the basis of their energy band diagrams. Solution

Q3 Draw a labelled energy band diagram for a solid which is an insulator. What is the main difference between this diagram and that of a semiconductor? Solution

Q4 What is meant by doping in semiconductors? What are p-type semiconductors? Solution

Q5 Explain, how an intrinsic semiconductor can be converted into (i) n-type, (ii) p-type semiconductor.Given one example of each and draw their energy band diagrams. Solution

Q6 What do semiconductors? Distinguish between them on the basis of energy band diagram. Solution

Q7 How are energy bands in solids formed? Explain, by drawing energy band diagrams, conduction in n-type and p-type semiconductors. Solution

Q8 Distinguish between intrinsic and extrinsic semiconductors. Solution

Q9 Distinguish between p-type and n-type semiconductors. Solution

Q10 Explain briefly what what is meant by extrinsic semiconductors, including the terms donor and acceptor impurities as well as p-type and n-type semiconductors. Solution

Q11 Using the concept of electron and hole currents, derive expression for the conductivity of a semiconductor. Solution