What is a transducer?

The audio signal used to modulate $60 \sin(2\pi \times 10^6 t)$ is $15 \sin(300\pi t)$. The depth of modulation is.......$\%$

The circuit used to separate information signals from the carrier wave is called a .......

Define the following terms:
$(a)$ Ground waves
$(b)$ Trade winds

The maximum amplitude for an amplitude modulated wave is found to be $12\, V$ while the minimum amplitude is found to be $3\, V$. The modulation index is $0.6\, x$ where $x$ is $....$

The maximum distance between the transmitting and receiving $TV$ towers is $65 \,km$. If the ratio of the heights of the $TV$ transmitting tower to receiving tower is $36: 49$, the heights of the transmitting and receiving towers respectively are (radius of earth $= 6400 \,km$)