Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Concepts Of Physics MCQ Edition [Volume 2]
Exam
Concepts Of Physics MCQ Edition [Volume 2]
Subject
Physics
Chapter
Laws of Thermodynamics

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Laws of Thermodynamics

A gas undergoes a process where its pressure varies linearly with...

A gas undergoes a process where its pressure varies linearly with volume from 10 kPa10 \text{ kPa}, 200 cc200 \text{ cc} to 50 kPa50 \text{ kPa}, 50 cc50 \text{ cc}. Determine the work done by the gas.

Options

  1. A−7.5 J-7.5 \text{ J}
  2. B4.5 J4.5 \text{ J}
  3. C−1.5 J-1.5 \text{ J}
  4. D−4.5 J-4.5 \text{ J}

Correct answer

D. −4.5 J-4.5 \text{ J}

Step-by-step solution

The work done by the gas in a process where pressure varies linearly with volume is given by the area under the P-V graph, which forms a trapezium.

Initial pressure P1=10 kPa=10×103 PaP_1 = 10 \text{ kPa} = 10 \times 10^3 \text{ Pa}

Final pressure P2=50 kPa=50×103 PaP_2 = 50 \text{ kPa} = 50 \times 10^3 \text{ Pa}

Initial volume V1=200 cc=200×10−6 m3V_1 = 200 \text{ cc} = 200 \times 10^{-6} \text{ m}^3

Final volume V2=50 cc=50×10−6 m3V_2 = 50 \text{ cc} = 50 \times 10^{-6} \text{ m}^3

The work done WW is calculated as:

W=12(P1+P2)(V2−V1)W = \dfrac{1}{2}(P_1 + P_2)(V_2 - V_1)

W=12(10×103+50×103)(50×10−6−200×10−6)W = \dfrac{1}{2}(10 \times 10^3 + 50 \times 10^3)(50 \times 10^{-6} - 200 \times 10^{-6})

W=12(60×103)(−150×10−6)W = \dfrac{1}{2}(60 \times 10^3)(-150 \times 10^{-6})

W=30×103×(−150×10−6)W = 30 \times 10^3 \times (-150 \times 10^{-6})

W=−4500×10−3 JW = -4500 \times 10^{-3} \text{ J}

W=−4.5 JW = -4.5 \text{ J}
Practice Laws of Thermodynamics on Quantrex Academy →

More from Laws of Thermodynamics

A paddle wheel is coupled to a mass of 12 kg via fixed frictionless pulleys. The paddle… Concepts Of Physics MCQ Edition [Volume 2]A 100 kg block is started with a speed of 2.0 m s^ -1 on a long, rough belt maintained in… Concepts Of Physics MCQ Edition [Volume 2]Water at 15^ ^ ^ ∘ C is contained inside a closed, thermally insulated copper vessel. The… Concepts Of Physics MCQ Edition [Volume 2]Water at 15^ ^ ^ ∘ C is contained inside a closed, thermally insulated copper vessel. The… Concepts Of Physics MCQ Edition [Volume 2]A 100 kg block is started with a speed of 2.0 m s^ -1 on a long, rough belt fixed in a… Concepts Of Physics MCQ Edition [Volume 2]A gas undergoes a process where its pressure varies linearly with volume from 10 kPa… Concepts Of Physics MCQ Edition [Volume 2]Determine the change in the internal energy of a gas confined in a rigid container when… Concepts Of Physics MCQ Edition [Volume 2]An ideal gas is taken from an initial state i to a final state f such that the ratio of… Concepts Of Physics MCQ Edition [Volume 2] Full Laws of Thermodynamics list All Concepts Of Physics MCQ Edition [Volume 2] PYQs