An amplitude modulated wave is represented by
C_m(t) = 10(1 + 0.2 cos 12560t) sin(111 $$\times$$ 10⁴t) volts. The modulating frequency in kHz will be ................. .

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

The amplitude of upper and lower side bands of A.M. wave where a carrier signal with frequency 11.21 MHz, peak voltage 15 V is amplitude modulated by a 7.7 kHz sine wave of 5V amplitude are $${a \over {10}}V$$ and $${b \over {10}}V$$ respectively. Then the value of $${a \over b}$$ is ____________.

A message signal of frequency 20 kHz and peak voltage of 20 volt is used to modulate a carrier wave of frequency 1 MHz and peak voltage of 20 volt. The modulation index will be :