10 POINT PLS HELP
Use the second law of thermodynamics to explain why a heat engine cannot be 100 percent efficient.

The air that we breath is made mostly of which gaseous molecule

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.

Adiagram show how a converging lens can produce a real image and virtual image