A triode has a transconductance (g_m) of 1,600\text{ micromhos}. The following table gives two sets of the plate voltage (E_b), the grid voltage (E_c) and the plate current (I_b). \begin{tabular}{c c c} E_b & E_c & I_b \\ 250\text{ V} & -22\text{ V} & 12.6\text{ mA} \\ 180 & -16.5 & 12.0 \end{tabular} Define the terms amplification factor and plate resistance and calculate them for the above case.

Distinguish between dia-, para- and ferromagnetism. Give an account of Weiss theory of ferromagnetism.

Explain, on the basis of bond structure, the behaviour of insulators and conductors. Describe the effect of adding donor or acceptor impurities on conduction in a semi-conductor. Explain the action of a p-n junction as a rectifier. \begin{aligned} \text{Mass of electron} &= 9.1 \times 10^{-31}\text{ kg} \\\\ 1\text{ a.m.u} &= 931\text{ MeV} \\\\ \text{Avogadro's numbers} &= 6.1 \times 10^{23}\text{ (gm-mole)}^{-1} \\\\ \varepsilon_0 &= 1/36\pi \times 10^{-9}\text{ f/m} \\\\ h &= 6.6 \times 10^{-27}\text{ erg sec} \\\\ c &= 3.0 \times 10^{10}\text{ cm/sec} \\\\ 1\text{ eV} &= 1.6 \times 10^{-19}\text{ erg} \\\\ &= 1.6 \times 10^{-19}\text{ joule} \end{aligned}

Why are NAND and NOR gates called universal gates? Give the logic diagram, Boolean equation and the truth table of NAND gate. Design an OR gate using only NAND gates.

Give the basic structure of a n-channel depletion type MOSFET. Draw the drain current-drain voltage characteristics both in depletion as well as in enhancement modes.