SATHEE: Thermodynamics and Thermochemistry 1 Question 41

Thermodynamics and Thermochemistry 1 Question 41

44. The reversible expansion ob an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct?

(2012)

(a) $T_{1} = T_{2}$

(b) $T_{3} > T_{1}$

(d) $Δ U_{isothermal} > Δ U_{adiabatic}$

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Solution:

(a) Since, change of state $(p_{1}, V_{1}, T_{1})$ to $(p_{2}, V_{2}, T_{2})$ is isothermal therefore, $T_{1} = T_{2}$ .

(b) Since, change of state $(p_{1}, V_{1}, T_{1})$ to $(p_{3}, V_{3}, T_{3})$ is an adiabatic expansion it brings about cooling of gas, therefore, $T_{3} < T_{1}$ .

(c) Work done is the area under the curve of $p - V$ diagram. As obvious from the given diagram, magnitude of area under the isothermal curve is greater than the same under adiabatic curve, hence $W_{isothermal} > W_{adiabatic}$

(d) $Δ U = n C_{v} Δ T$

In isothermal process, $Δ U = 0$ as $Δ T = 0$

In adiabatic process, $Δ U = n C_{v} (T_{3} - T_{1}) < 0$ as $T_{3} < T_{1}$ .

$\Rightarrow Δ U_{isothermal} > Δ U_{adiabatic}$

NOTE Here only magnitudes of work is being considered otherwise both works have negative sign.

Thermodynamics and Thermochemistry 1 Question 41

44. The reversible expansion ob an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct?

Solution:

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Thermodynamics and Thermochemistry 1 Question 41

44. The reversible expansion ob an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct?

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

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