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Question #42536

Difficulty: 8/10 | 🟢 Free

The Question

A rigid container holds an ideal diatomic gas. The container loses heat to the surrounding environment (at a constant temperature Tenv=300 KT_{\text{env}} = 300\text{ K}) at a rate dQlossdt=H(T−Tenv)\frac{dQ_{\text{loss}}}{dt} = H(T - T_{\text{env}}), where H=1 W/KH = 1\text{ W/K} and TT is the instantaneous gas temperature.

A semiconductor heater inside the container is powered by a constant voltage source VV. The resistance of the heater depends on the gas temperature as R(T)=R0eβ/TR(T) = R_0 e^{\beta/T}, where β=600ln⁡2 K\beta = 600 \ln 2\text{ K} and V2R0=600 W\frac{V^2}{R_0} = 600\text{ W}. Assuming the heater is always in thermal equilibrium with the gas, and the gas is initially at 300 K300\text{ K}, what is the final steady-state temperature of the gas?

Options

  • A.

    600 K600\text{ K}

  • B.

    450 K450\text{ K}

  • C.

    900 K900\text{ K}

  • D.

    750 K750\text{ K}

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Variable_Constraint

Develop pure symbolic logic skills by mastering algebraic constraints without relying on numerical data.

Concepts Behind This Question

Internal Energy Dependency|Molecular Degrees of Freedom|Dynamic Resistance (AC Resistance)

Why This Question Is Tricky

Common Mistakes

This question tests the student's ability to couple thermodynamic heat transfer with dynamic electrical resistance.

A common lethal mistake is assuming the heater's power output is constant.

Students often calculate the initial resistance at T=300 KT = 300\text{ K} (R=4R0R = 4R_0) and the corresponding initial power (150 W150\text{ W}).

Equating this constant power to the heat loss yields an incorrect steady-state temperature of 450 K450\text{ K}.

This ignores the non-linear feedback loop: as the gas heats up, the semiconductor's resistance drops, increasing the power dissipation until a true dynamic equilibrium is reached at 600 K600\text{ K}.

Quick Facts About This Question

Question Information

SubjectPhysics
ChapterThermodynamics - Class 11 Part 2
ConceptInternal Energy Dependency
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree