Embibe Experts Solutions for Chapter: Electronic Devices Semiconductors, Exercise 2: Level 2

The density of electrons and holes in a pure germanium sample at room temperature are equal and its value is $3\times {10}^{16}$ per ${\mathrm{m}}^3$. On doping with Aluminium, increases to $4.5\times {10}^{22}$ per ${\mathrm{m}}^3$. Then the electron density in doped germanium is $k\times {10}^{10} {\mathrm{m}}^{-3}$. The value of $k$ is:

If breakdown voltage of Zener diode is $6 \mathrm{V}$, then the value of $I_2$ will be,

For the given logic gate circuit, to get output as $1$ at $R,$ find the input of $X,$ if input value of $Y$ is zero.

A digital signal -

The maximum and minimum amplitude of an amplitude modulated wave is $16 \mathrm{V}$ and $8 \mathrm{V}$ respectively. The modulation index for this amplitude modulated wave is $x\times {10}^{-2}.$ The value of $x$ is

If the highest frequency modulating a carrier is $5 \mathrm{kHz},$ then the number of AM broadcast stations accommodated in a $90 \mathrm{kHz}$ bandwidth are _______ .

Choose the incorrect statement(s):

(i) Skywave communication takes place at frequency above approximately $30 \mathrm{MHz}$.

(ii) Amplitude modulated (AM) radio communication is mostly done by ground wave propagation.

(iii) $\mathrm{F}$ layer of ionosphere is mostly responsible for skywave propagation.

(iv) Bandwidth required for transmission of video signal is generally more than audio signal.

An audio signal of $1 \mathrm{kHz}$ is used to modulate a carrier of $500 \mathrm{kHz}$. The bandwidth required is