Distinguish between substitutional and interstitial impurities with the help of a diagram.
See Answer →How does the Fermi energy of n- and p- type semiconductors change with dopant concentration?
See Answer →Show that the group velocity is zero at the zone boundary for a linear diatomic chain.
See Answer →Plot the variation of electrical resistivity with temperature for an ideal metal and a superconductor.
See Answer →The energy of the lowest allowed level for an electron in a 1-D box is 8.0 eV. Can the electron ever have an energy of 200 eV? Justify.
See Answer →List the symmetries observed in a methane molecule.
See Answer →Write down the electronic configuration of the Ge atom. What type of bonding would you expect to find in Ge?
See Answer →Is it possible to carry out electron diffraction studies in air? Explain.
See Answer →Write down the Miller indices of a set of parallel planes which make intercepts in the ratio of 4a1:4a2 on the x and y axes and are parallel to the z-axes.
See Answer →a) The earth and the sun are 8.3 light-minutes apart in the same inertial frame. Two events occur at t = 0 on the earth and t = 3 minutes on the sun respectively. Calculate the time difference between the events according to an observer moving at u = 0.6c from the earth to the sun. (1 light minute is the distance travelled by light in one minute.)
See Answer →c) Using the expression of Bose-Einstein distribution function for photons
derive Plancks Law and show that (i) Rayleigh-Jeans Law, and (ii) Wien’s Law follow from it at low & high frequencies.
See Answer →Design a 5-bit DAC using op-amp adder. Specify the minimum op-amp supply voltage required for proper operation. Calculate the step size for digital input of 0-5 V. What is % resolution of the DAC?
See Answer →Convert 732.5210 into its octal equivalent.
See Answer →b) What is a Gibbs paradox? How did it arise?
See Answer →a) Establish Boltzmann relation between entropy (S), and thermodynamic probability
A triangular wave of V amplitude and 10 MHz frequency is generated at the output of an op-amp. Calculate the minimum slew rate of the op-amp used.
Design a zener regulator to give regulated 10 V dc output with maximum load current of 100 mA. Consider that input unregulated dc supply is 15 V and Write down the voltage and power ratings of the zener diode and power rating of series resistor Rs for your circuit.
b) Derive Einstein’s formula for mean square displacement of a Brownian particle.
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