For an amplitude-modulated wave, the audio frequency is $500 \, \text{cycles/second}$. What is the actual carrier frequency in $\text{cycles/sec}$?

In a communication system,noise is most likely to affect the signal:

The modulation index for an $A.M.$ wave having maximum and minimum peak-to-peak voltages of $14\,mV$ and $6\,mV$ respectively is:

In amplitude modulation,if a message signal of $5 \ kHz$ is modulated by a carrier wave of frequency $900 \ kHz$,then the frequencies of the side bands are

For television broadcasting,the frequency employed is normally in the range of,

The modulation index used in amplitude modulation of a message signal of peak voltage $10 \,V$ is $0.5$. By how much should the peak voltage of the carrier signal be changed, so as to obtain the modulation index of $0.8$, keeping the peak voltage of the message signal the same as before?