Describe the spectra for a spectroscopic binary for a system comprised of an f-type and l-type star. assume that the system is too far away to be able to easily observe the l-type star.

True or false: the cycle of seasons on the earth is caused by the tilt of the earth on its axis toward and away from the sun.

Infrared rays have a shorter wavelength than question 11 options: x-rays. ultraviolet rays. radio waves. gamma rays.

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.