The worst case signal-to-noise ratio at the output of an FM detector occurs when: a. the desired signal is 90 degrees out of phase with the intelligence signal.
b. the desired signal is 90 degrees out of phase with the noise signal.
c. the noise signal is 90 degrees out of phase with the resultant signal of adding the signal to the noise.
d. the desired signal is 90 degrees out of phase with the resultant signal of adding the signal to the noise.

An air-conditioning system consists of a heating section and an evaporative cooler. air enters the heating section at 10°c and 70 percent relative humidity at a rate of 30m^3/min, and it leaves the evaporative cooler at 20°c and 60 percent relatively humidity. if the air conditioning system operates at a total pressure of 98 kpa, determine (a) the temperature and relative humidity of the air when it leaves the heating section, (b) the rate of heat transfer in the heating section, and (c) the rate of water added to air in the evaporative cooler