Communication-System-Quiz-9

Communication System Quiz-9

Dear Readers,

As per analysis for previous years, it has been observed that students preparing for NEET find Physics out of all the sections to be complex to handle and the majority of them are not able to comprehend the reason behind it. This problem arises especially because these aspirants appearing for the examination are more inclined to have a keen interest in Biology due to their medical background. 

Furthermore, sections such as Physics are dominantly based on theories, laws, numerical in comparison to a section of Biology which is more of fact-based, life sciences, and includes substantial explanations. By using the table given below, you easily and directly access to the topics and respective links of MCQs. Moreover, to make learning smooth and efficient, all the questions come with their supportive solutions to make utilization of time even more productive. Students will be covered for all their studies as the topics are available from basics to even the most advanced.

Q81. In the above question, if oscillator output is modulated by audio frequencies upto 10 kHz, the frequency range occupied by the side bonds will be

•  711.9 kHz to 712.1 kHz
•  692 kHz to 732 kHz
•  702 kHz to 722 kHz
•  71.2 kHz to 70.2 kHz

Solution
Here, f_m=10 kHz 

 ∴f_SB=f_c±f_m=(712±10)=kHz =702 kHz and 722 kHz

Q82.In pulse modulation of analog signals, common pulse system employed are

•  Pulse amplitude modulation (PAM)
•  Pulse position and pulse duration modulation (PPM and PDM)
•  Pulse code modulation (PCM)
•  All of the above

Solution
All the four pulse systems are employed in pulse modulation

Q83.  Which of the following is not the main characteristic of laser beam?

•  High irradiance
•  High divergence
•  Highly monochromatic
•  Highly coherent

Solution
Laser beam is almost perfectly parallel and have low divergence.

Q84. The antenna current of an AM transmitter is 8 A when only the carrier is sent, but it increases to 8.93 A when the carrier is modulated by single sine wave. Find the percentage modulation.

•  60.1 %
•  70.1 %
•  80.1 %
•  50.1%

Solution
                  

Q85.When ω_m is the modulation frequency in frequency modulation, the modulation index is proportional to

•  ω_m
•  ω_m²
•  1/ω_m
•  1/ω_m²

Solution
                     

 

Q86. A double star system consists of two stars A and B which have time period T_A and T_B. Radius R_A and R_B and mass M_A and M_B. Choose the correct option.

•  If T_A> T_B then R_A> R_B
• If T_A> T_B then M_A> M_B
•  (TA/T_B )²=(R_A/R_B )³
•  T_A= T_B

Solution
In case of binary star system angular velocity and hence the time period of both the stars are equal.

Q87.A laser beam is used for carrying out surgery because it

•  Is highly monochromatic
•  Is highly coherent
•  Is highly directional
•  Can be sharply focused

Solution
A laser beam is used for carrying out surgery because, it can be sharply focused due to a very high energy per unit area is involved at a location.

Q88.A receiver reconstructs the original message after propagation through the channel.

•  May be true
•  May be false
•  May be true or false
•  Is certainly true

Solution
The statement is invariably true

Q89.The diameter of an optical fiber is

•  10^-5m
•  10^-4m
•  10^-3cm
•  10^-2cm

Solution
The diameter of optical fiber is 10^-4 cm

Q90. The characteristic impedance of a coaxial cable is of the order of

•  50 W
•  200 W
•  270 W
• None of these

Solution
The characteristic impedance of a coaxial cable is of the order of 270 Ω.