Describe the Frank-Hertz experiment. Discuss its results and outline its limitations.
Explain potential energy barriers for the charge carriers in BJT. Describe how the transistor works as a voltage amplifier.
Discuss Bloch's theorem, and explain the Kronig-Penny model to describe the behaviour of electrons in a periodic potential. Details of derivation are not required.
Attempt any Eight questions
[8×5=40]Elucidate Hall effect and hence describe the significance of Hall coefficient.
What is a memory circuit? Explain.
Explain the meaning of "space quantization" for an electron. If the spin quantum number of an electron is s = 1/2, how many possible orientations of its spin angular momentum vector exist with respect to an external magnetic field? Specify the values of the spin magnetic quantum number ms for each orientation.
A ball of mass 0.3 kg and radius 0.1 m rolls along a ground with a speed of 4 m/s. It comes to a rest at an elevation of 0.50 m. How far up the slope does it roll? It is given that the moment of inertia of the ball is I = 2mr2/5.
Calculate the uncertainty in the momentum of an electron if the uncertainty in its position is 1 Å.
A proton is moving with velocity v = (3 × 105i + 7 × 105k) m/s in a region where there is a magnetic field B = 0.4j T. Find the force experienced by the proton.
The density of aluminium is 2.70 g/cm3 and its molecular weight is 26.98 g/mol. Calculate the Fermi energy. (Aluminium is trivalent.)
The energy gap in silicon is 1.1 eV, whereas in diamond it is 6 eV. What conclusion can you draw about the transparency of the two materials to visible light, 4000 Å to 7000 Å?
Given the distributive law of Boolean algebra A(B + C) = AB + AC, make an appropriate truth table to prove it.