PYQ Bank

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

With the help of a schematic diagram, show how entropy and specific heat vary with temperature for a superconductor.

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

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.

Distinguish between diamagnetic, paramagnetic and ferromagnetic substances.

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

Obtain Laue's equations for X-ray diffraction by crystals. Show that these are consistent with the Bragg's law.

The primitive translation vectors of a two-dimensional lattice are \hat{a}=2\hat{i}+\hat{j},\quad \hat{b}=2\hat{j}. Determine the primitive translation vectors of its reciprocal lattice.

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

What is the difference between direct and indirect band gap semiconductors? Which one is suitable for use in solar cells?

Distinguish between a superconductor and perfect conductor. Explain what is a Cooper pair.

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.

Design a transistor based Colpitt oscillator which can oscillate at 9\,\mathrm{MHz}. Explain how the oscillations are created and sustained.

Draw the device structure of a p-n junction solar cell and explain how light energy is converted into electrical energy. Draw and explain its I-V characteristics.

Differentiate between n-p-n and p-n-p transistors. Give their device structure and biasing circuits when used as an amplifier.

Describe an operational amplifier based integrator. Using operational amplifier integrators, design a circuit to solve the following differential equation: \frac{d^2v}{dt^2}+2\frac{dv}{dt}+3v=0

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

Find an expression for lattice specific heat of a solid, and its low and high temperature limits. What is Debye temperature?