**P. 4079.** There is a sample of neon in a cylinder which is closed by a piston. The gas is compressed such that its volume decreased to two-thirds of the original volume. The *p*, *V* graph of the process is a straight line segment. In the final state the pressure of the gas is twice as much as it was originally.

*a*) By what factor did the absolute temperature of the gas increased?

*b*) How much thermal energy was absorbed by the gas from its environment?

*c*) How can this process be realized?

(5 points)

**P. 4081.** A neutral and a charged capacitor which have the same capacitance are connected in parallel.

*a*) To what fraction of the original energy does the total energy of the system decrease, after connecting the condensers?

*b*) What happens to the ``lost energy''?

*c*) What is the correct answer to the previous question if all the conductors are superconductors.

(5 points)