Why can blue light and yellow light combine to produce white light?
a. because blue, yellow, and white are primary colors.
b. they absorb each other s wavelengths.
c. they are complementary colors of light.
d. they are both primary colors of light.

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.