For VHF signal broadcasting, ___________ km² of maximum service area will be covered by an antenna tower of height 30 m, if the receiving antenna is placed at ground. Let radius of the earth be 6400 km. (Round off to the Nearest Integer) (Take $$\pi$$ as 3.14)

If the highest frequency modulating a carrier is 5 kHz, then the number of AM broadcast stations accommodated in a 90 kHz bandwidth are _________.

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

A signal of 0.1 kW is transmitted in a cable. The attenuation of cable is $$-$$5 dB per km and cable length is 20 km. The power received at receiver is 10^$$-$$x W. The value of x is ________.

[Gain in $$dB = 10{\log _{10}}\left( {{{{P_o}} \over {{P_i}}}} \right)$$]