Explain with the help of a neat diagram the working of an RC coupled common emitter amplifier.

{ifos-q-8-095-fig-1} Find the Boolean algebra expression for the above system.

Determine the values of emitter current and the collector current of the transistor having \alpha = 0\cdot98 and collector to base leakage current I_\text{CBO} = 4\ \mu\text{A}. The base current is 50\ \mu\text{A}.

Why does the resistance of a semiconductor decrease with increase in temperature ?

What do you understand by spontaneous magnetization below Curie temperature ? Explain with an appropriate diagram, the occurrence of a hysteresis loop in a ferromagnetic material.

Define the terms critical magnetic field and critical temperature in a superconductor. Find the magnetic field strength necessary to destroy the superconductivity in a sample of lead at 4\cdot2\text{ K}. The critical magnetic field at 0\text{ K} is 0\cdot80\text{ Tesla} and the critical temperature is 7\cdot2\text{ K}.

Distinguish between diamagnetic, paramagnetic and ferromagnetic substances.

Describe the following laws of Boolean algebra with one application each to logic circuit :

(i) Commutative law of addition

(ii) Associative law of addition

(iii) Associative law of multiplication

(iv) Distributive law

Distinguish between a normal conductor, a superconductor and a semiconductor. How a p-type semiconductor differs from an n-type?

What are logic gates and truth tables? Obtain the truth table of a two-input OR gate.

Give schematic diagrams to distinguish between n\text{-}p\text{-}n and p\text{-}n\text{-}p transistors.

Describe the phenomenon of Meissner effect and its importance in the study of superconductors.

Give an elementary outline of high-temperature superconductors and their experimental status.

Explain the operation of NOR gate with a logical diagram and truth table. Show how NOR gate can be used as Universal gate.

What are called intrinsic and extrinsic semiconductors ?

Explain the term critical magnetic field in a superconductor. How does the critical magnetic field vary with temperature in Type-I and Type-II superconductors ? What is Meissner effect ?

With a suitable circuit diagram and theory explain the use of OP-Amps as

(i) Adder, and

(ii) Integrator.

Construct the following function with logic gates : Y = (A + B) (C + D + E) (F + G + H + I) (JKL)

A silicon diode operates at a forward bias voltage of 0\cdot 4\text{ V}. Calculate the factor by which the current will be multiplied when the temperature is increased from 25^\circ\text{C} to 150^\circ\text{C} (\eta for \text{Si} = 2).

What is ac Josephson effect ? Derive an expression for the current flowing through the junction formed by two superconducting films separated by an insulator.