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Relation between volume and pressure of one mole of an ideal gas is given as \( V^{2}=\left(\frac{P_{0}-P}{a}\right) \), where \( P_{0} \) and \( a \) are positive constants. If maximum temperature attained by the gas during this process is \( \frac{A P_{0}}{B R} \sqrt{\frac{P_{0}}{B a}} \), then value of \( (A+B) \) is equal to . \( A \) and \( B \) are coprime integers) ( \( R \) is universal gas constant) |
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Answer» Given v2 = \(\left(\cfrac{p_0-p}a\right)\) p0 - p = av2 p = p0 - av2 ......(i) \(\because\) pv = nRT p = \(\cfrac{nRT}v\) \(\cfrac{nRT}v\) = p0 - av2 T = \(\cfrac{p_0v}{nR}\) - \(\cfrac{av^3}{nR}\)....(ii) \(\left(\cfrac{dT}{dv}\right)\) = 0 \(\left(\cfrac{dT}{dv}\right)\) = \(\cfrac{p_0}{nR}\) - \(\cfrac{3av^2}{nR}\) = 0 \(\cfrac{3av^2}{nR}\) = \(\cfrac{p_0}{nR}\) v2 = \(\cfrac{p_0}{3a}\) v = \(\sqrt{\cfrac{p_0}{3a}}\) there value put in equation (ii) Tmax = \(\cfrac{p_0v}{nR}\) = \(\cfrac{av^3}{nR}\) = \(\cfrac{p_0}{nR}\) \(\left(\sqrt{\cfrac{p_0}{3a}}\right)\) - \(\cfrac{a}{nR}\) \(\left({\cfrac{p_0}{3a}}\right)^{3/2}\) T = \(\sqrt{\cfrac{p_0}{3a}}\) \(\left(\cfrac{p_0}{nR}-\cfrac{a}{nR}\times\cfrac{p_0}{3a}\right)\) T = \(\sqrt{\cfrac{p_0}{3a}}\) \(\left(\cfrac{3p_0-p_0}{3nR}\right)\) T = \(\cfrac{2p_0}{3nR}\) \(\sqrt{\cfrac{p_0}{3a}}\) Give T = \(\cfrac{A\,p_0}{B\,nR}\) \(\sqrt{\cfrac{p_0}{Ba}}\) then A = 2 B = 3 Then value at A + B equal to = 2 + 3 = 5 |
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