$A$ carrier wave is used to transmit a message signal. If the peak voltage of the modulating signal and the carrier signal are increased by $1 \%$ and $3 \%$ respectively,the modulation index is changed by (in $\%$)

The maximum and minimum amplitude of an amplitude modulated wave is $16\, V$ and $8\, V$ respectively. The modulation index for this amplitude modulated wave is $x \times 10^{-2}$. The value of $x$ is .........

In amplitude modulation,the message signal $V_{m}(t) = 10 \sin(2 \pi \times 10^{5} t) \text{ V}$ and the carrier signal $V_{c}(t) = 20 \sin(2 \pi \times 10^{7} t) \text{ V}$. The modulated signal contains the message signal with lower sideband and upper sideband frequencies. Therefore,the bandwidth of the modulated signal is $\alpha \text{ kHz}$. The value of $\alpha$ is:

$A$ carrier is simultaneously modulated by two sine waves with modulation indices of $0.4$ and $0.3$. The resultant modulation index will be

An optical fibre communication system works on a wavelength of $1.3 \mu m$. The number of subscribers it can feed if a channel requires $20 \ kHz$ is:

The antenna current of an $AM$ transmitter is $8 \ A$ when only the carrier is sent,but it increases to $8.96 \ A$ when the carrier is modulated by a sine wave. The percentage of modulation is: (in $\%$)