$A$ wave is represented as $e = 10\,(1 + 6\, \sin(50t)) \sin(10^8t)$. The modulation index is:

In a communication system,the process of superimposing a low-frequency signal on a high-frequency wave is known as:

Given below are two statements
Statement $I:$ For transmitting a signal,the size of the antenna $(l)$ should be comparable to the wavelength of the signal (at least $l = \frac{\lambda}{4}$ in dimension).
Statement $II:$ In amplitude modulation,the amplitude of the carrier wave remains constant (unchanged).
In the light of the above statements,choose the most appropriate answer from the options given below.

Which of the following is the communication channel in case of radio communication?

The waves used for line-of-sight $(LOS)$ communication are

For $100\%$ modulation,what should be the value of the minimum amplitude $(E_{min})$ of the modulated wave?