Direction: A football was inflated to a gauge pressure of 1 bar when the ambient temperature was 15°C. When the game started next day, the air temperature at the stadium was 5°C. Assume that the volume of the football remains constant at 2500 cm3.
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A gas contained in a cylinder is compressed, the work required for compression being 5000 kJ. During the process, heat interaction of 2000 kJ causes the surroundings to be heated. The changes in internal energy of the gas during the process is
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- –7000 kJ
- –3000 kJ
- +3000 kJ
- +7000 kJ
Correct Option: D
q = u + w
2000 = u – 5000
u = 7000
