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  • EM waves of low frequency (like sound wave - 20 Hz to 20 KHz ) cant be transmitted over a long distance because Option: 1 That would require a v

EM waves of low frequency (like sound wave - 20 Hz to 20 KHz ) cant be transmitted over a long distance because 

Option: 1

That would require a very low antena (few kms long)


Option: 2

Very low power signals are radiated when low frequency signals are transmitted 


Option: 3

Both 1 and 2


Option: 4

none 


Answers (1)

best_answer

As we have learned

Need for Modulation -The sound wave ( 20 Hz to 20 kHz ) cannot be transmitted directly from one place to another due to any reason.

For signal transmission over a long distance with high efficiency, The antenna length  

Should be at least 1/4th of the wavelength of the signal. Now, for low-frequency EM waves, the wavelength will be enormously high (running into Kms ). Antenna thus would require to  be few Kms long 

The power required from the antenna is inversely proportional  to the square of the wavelength 

P \propto \left ( \frac{1}{\lambda} \right )^2 , Thus for high frequency and low wavelength signals, power-related is very low. Hence both 1 and 2 are correct 

 

 

 

 

Posted by

shivangi.bhatnagar

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