Semiconductors and Electronic Devices MCQ Questions & Answers in Modern Physics | Physics

We can simplify the gate circuit as

Here, gates-I and II are NOR gates. The output $$\overline {\left( {A + B} \right)} $$   of gate-I will appear as input of gate-II. The final output is
$$Y = \overline {A + B} = A + B$$
This is the Boolean expression of OR gate whose truth table is given below

A	B	Y
0	0	0
0	1	1
1	0	1
1	1	1

The emitter produces majority charge carriers, so in order that these reach collector, emitter is forward biased, while collector is reverse biased.

(A) In insulators, energy gap is of the order of $$5$$ to $$10\,eV$$  and it is practically impossible to impart this much amount of energy to the electrons in valence band so as to jump to conduction band.
So,choice (A) is correct.
(B) In semiconductors, with the rise in temperature more electrons from valence band jump to conduction band and this results in increase in conductivity. So, choice (B) is correct.
(C) In conductors, the conduction band is either partially filled or the conduction band overlaps on the valence band. So, choice (C) is correct.
(D) In semiconductor, resistivity decreases with increase in temperature.
So,choice (D) is wrong.

For forward bias, p-side must be at higher potential than $$n$$-side. $$\Delta V = \left( + \right)Ve$$

Input frequency, $$f = 50\,Hz \Rightarrow T = \frac{1}{{50}}$$
For full wave rectifier, $${T_1} = \frac{T}{2} = \frac{1}{{100}} \Rightarrow {f_1} = 100\,Hz.$$