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प्रश्न
The internal energy of a gas is given by U = 1.5 pV. It expands from 100 cm3 to 200 cm3against a constant pressure of 1.0 × 105 Pa. Calculate the heat absorbed by the gas in the process.
उत्तर
Let change in volume of the gas be ∆V.
∆V = (200 − 100) cm3 = 100 cm3
= 10−4 m3
p = 1 × 105 Pa
Change in internal energy of the system, ∆U = 1.5 pV
∆U = 1.5 × 105 × 10−4 = 15 J
∆W = p∆V
= 105 × 10−4 = 10 J
Using the first law of thermodynamics, we get
∆Q = ∆U + ∆W = 10 + 15 = 25 J
Thus, heat absorbed by the system is 25 J.
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