(a)What is a pn junction? How is it formed? (b) Sketch the energy-band picture for i} an intrinsic iin-type iii} a p-type semiconductor Indicates the positions of the fermi, the donor & the acceptor levels. (c) What is meant by rectifier? (d) Compare the performance measure of different filters. (e) Why Transistor is called Current Controlled Device? (f)What is early effect? How does it modify the V-I characteristics of a BJT? (g) What is meant by operating point? Explain its significance (h)What is the condition for thermal stability and thermal resistance? (i) Explain when a FET acts as a voltage variable resistor. (j) Explain the drain and transfer characteristics of a JFET in details