Embibe Experts Solutions for Chapter: Communication Systems, Exercise 2: Exercise - 2

Which of the following four alternatives is not correct? We need modulation,

A radar has a power of $1 \mathrm{kW}$ and is operating at a frequency of $10 \mathrm{GHz}$. It is located on a mountain top of height $500 \mathrm{m}$. The maximum distance up to which it can detect object located on the surface of the earth (radius of the earth$=6.4\times {10}^6 \mathrm{m}$) is,

For sky wave propagation, the radio waves must have a frequency range in between:

Long range radio transmission is possible when the radio waves are reflected from the ionosphere. For this to happen, the frequency of the radio waves must be in the range,

A signal of $5 \mathrm{kHZ}$ frequency is amplitude modulated on a carrier wave of frequency $2 \mathrm{MHz}$. The frequencies of the resultant signal is/are:

Choose the correct statement.

In amplitude modulation, sinusoidal carrier frequency used is denoted by ${\mathrm{\omega }}_{\mathrm{c}}$ and the signal frequency is denoted by ${\mathrm{\omega }}_{\mathrm{m}}$. The bandwidth $\left(∆{\mathrm{\omega }}_{\mathrm{m}}\right)$ of the signal is such that $∆{\mathrm{\omega }}_{\mathrm{m}}\ll {\mathrm{\omega }}_{\mathrm{c}}$. Which of the following frequency is not contained in the modulated wave?

A telephonic communication service is working at carrier frequency of $10 \mathrm{GHz}$. Only $10\%$ of it is utilized for transmission. How many telephonic channels can be transmitted simultaneously if each channel requires a bandwidth of $5 \mathrm{kHz}$?