Broadcasting antennas are generally

The wavelength of the carrier waves in a modern optical fiber communication network is close to ........ $nm$.

What is the modulation index of the $AM$ wave shown in the figure?

$A$ diode detector is used to detect an amplitude modulated wave with $60\%$ modulation,using a capacitor of $250 \ pF$ in parallel with a resistor of $100 \ k\Omega$. What is the maximum modulation frequency that can be detected by this circuit?

The maximum amplitude of an $AM$ wave is found to be $20 \,V$ while its minimum amplitude is $4 \,V$. The modulation index is

An amplitude modulated wave is represented by $10[1+0.6 \sin(40 \times 10^3 t)] \sin(4 \times 10^6 t)$ volt,where $t$ is in seconds. The ratio of the upper sideband frequency to the lower sideband frequency is: