$A$ carrier wave of peak voltage $12 \, V$ is used to transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of $75 \%$? ...... $V$

If the length of an antenna is $150 \,cm$,the transmission frequency is . . . . . . $MHz$. (Speed of light in vacuum $= 3 \times 10^8 \,ms^{-1}$)

If a receiving station on the ground is receiving a frequency of $10 \text{ MHz}$, the mode of propagation is...

In amplitude modulation,

The modulation frequency of an $AM$ radio station is $250\, kHz$,which is $10\%$ of the carrier wave. If another $AM$ station approaches you for license,what broadcast frequency will you allot? (Note: The interval between two carrier frequencies should be at least two times the modulation frequency to avoid interference.)

$A$ signal of frequency $10 kHz$ and peak voltage $10 V$ is used to amplitude modulate a carrier of frequency $1 MHz$ and peak voltage $20 V$. The side-band frequencies in $kHz$ are