There is a pressure volume graph with the gas changes shown, forming a rectangle. The corners are labled A to D starting from the upper left corner heading on to the right until it returns to point A again.
The question is at what point, or line is the internal energy of the gas greatest?
Like this, except the numbers are different.
ΔU = Q-W
The Attempt at a Solution
The prior question asked to find the temperatures at each point provided A was at 300K.
So I thought that the internal energy of the gas would be maximum when it's at low volume and high pressure, therefore at point A. But at B & C it is hotter meaning it must have gained energy from an external source. So going to B it has expanded and gained energy. But by expanding it does work loosing internal energy right? So how come its temperature got higher? Honestly these graphs just confuse me a lot, I'd really appreciate any help.
Thanks is advance:)