Physics: Thermodynamics

A sample of an ideal gas is taken through the cyclic process abca as shown in the figure. The change in the internal energy of the gas along the path ca is – 180 J, The gas absorbs 250 J of heat along the path ab and 60 J along the path bc. The work down by the gas along the path abc is:

A litre of dry air at STP expands adiabatically to a volume of 3 litres. If γ = 1.40, the work done by air is: (3^1.4 = 4.6555) [Take air to be an ideal gas]

A thermodynamic cycle xyzx is shown on a V-T diagram.

The P-V diagram that best describes this cycle is:
(Diagrams are schematic and not to scale)

Starting at temperature 300 K, one mole of an ideal diatomic gas (γ = 1.4) is first compressed adiabatically from volume V₁ to V₂ = V₁/16. It is then allowed to expand isobarically to volume 2V₂. If all the processes are the quasi-static then
the final temperature of the gas (in °K) is (to the nearest integer) ______.

Which of the following is an equivalent cyclic process corresponding to the thermodynamic cyclic given in the figure?
where, 1 → 2 is adiabatic.
(Graphs are schematic and are not to scale)