Hi there. I have a problem solving this task: Insulated tank of volume 5 m3 and with a valve was filled with perfect di-atomic (κ = 1.4) gas at pressure 4 bar.
Initially the valve was closed. A 12 kW electric heater was installed inside the tank. The heater was turn on and at the
same time the exit valve was opened. The gas which is leaving the tank through the valve has constant temperature.
Calculate the time needed to decrease the pressure in the tank to 2 bar. The gas is not known (it's not air, only k=1.4 is known)