Question

The standard value for intermediate frequency in AM receiver is
A. $10.5\,KHz$
B. $55\,KHz$
C. $455\,KHz$
D. none of the above.

Answer 1

Hint- An AM receiver detects the variation in amplitude of the incoming radio waves at a particular frequency and then amplifies this change.
An intermediate frequency is a frequency to which the carrier wave is shifted as an intermediate step in transmission or reception.

Step by step solution:
A receiver is an electronic device used in communication systems that receives radio waves and converts the information carried by them into usable form.
An AM receiver detects the variation in amplitude of the incoming radio waves at a particular frequency and then amplifies this change. Am stands for amplitude modulation. The receiver is used to extract the desired information from the radio waves that are received. The receiver uses electronic filters to separate the required radio frequency signal from all other signals that are picked up by the antenna. Then an amplifier is used to increase the power of the signal for further processing.
There are two types of modulation which are used in analogue radio broadcasting systems. They are FM and AM. In AM amplitude is modulated and in FM frequency is modulated.
An intermediate frequency is a frequency to which the carrier wave is shifted as an intermediate step in transmission or reception. Intermediate frequency is used to improve the frequency selectivity. In cases where several stages of filters are used, we can set all of them to a fixed intermediate frequency so that it becomes easier to tune.
In an AM receiver the most commonly used frequency is $445\,Hz$.

So, the answer is option C.

Note: The intermediate frequency differs depending upon the modulation used.
In AM receiver it is $445\,Hz$. But, in the case of FM receivers the commonly used intermediate frequency is $10.7\,MHz$.