Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Heat and Thermodynamics question

2016 · 9 Apr · Shift 1 · Q62
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Physics
  4. /Heat and Thermodynamics
  5. /2016 · 9 Apr · Shift 1 · Q62

Heat and Thermodynamics question

2016 · 9 Apr · Shift 1 · Q62

JEE MainPhysicsHeat and ThermodynamicsMCQ+4 / −1
The ratio of work done by an ideal monoatomic gas to the heat supplied to it in an isobaric process is :
  1. A
    35{3 \over 5}53​
  2. B
    23{2 \over 3}32​
  3. C
    32{3 \over 2}23​
  4. D
    25{2 \over 5}52​
View written solutionFree

Correct answer: D

  1. For an isobaric process, the work done by an ideal gas is W=PΔVW = P\Delta VW=PΔV

  2. Using the ideal gas law for a fixed amount of gas, PΔV=nRΔTP\Delta V = nR\Delta TPΔV=nRΔT so, W=nRΔTW = nR\Delta TW=nRΔT

  3. The heat supplied in an isobaric process is Q=nCPΔTQ = nC_P\Delta TQ=nCP​ΔT

  4. For an ideal monoatomic gas, CV=3R2C_V = \frac{3R}{2}CV​=23R​ and CP=CV+R=3R2+R=5R2C_P = C_V + R = \frac{3R}{2} + R = \frac{5R}{2}CP​=CV​+R=23R​+R=25R​

  5. Therefore, Q=n(5R2)ΔTQ = n\left(\frac{5R}{2}\right)\Delta TQ=n(25R​)ΔT

  6. Now the required ratio is WQ=nRΔTn(5R2)ΔT\frac{W}{Q} = \frac{nR\Delta T}{n\left(\frac{5R}{2}\right)\Delta T}QW​=n(25R​)ΔTnRΔT​

    Cancelling common terms, WQ=R5R/2=25\frac{W}{Q} = \frac{R}{5R/2} = \frac{2}{5}QW​=5R/2R​=52​

  7. Hence, the correct option is 25\boxed{\frac{2}{5}}52​​ which is Option D.

PreviousNext

More from Heat and Thermodynamics

  • 200 g water is heated from 40oC to 60oC. Ignoring the slight expansion of water, the change in its internal energy is close to (Given specific heat of water = 4184 J/kg/K) :2016 · MCQ
  • Which of the following shows the correct relationship between the pressure ‘P’ and density ρ of an ideal gas at constant temperature ?2016 · MCQ
  • ′n′ moles of an ideal gas undergoes a process A→B as shown in the figure. The maximum temperature of the gas during the process will be : Includes diagram2016 · MCQ
  • An ideal gas undergoes a quasi static, reversible process in which its molar heat capacity C remains constant. If during this process the relation of pressure P and volume V is given by PVn= constant, then n is given by (Here…2016 · MCQ
  • A pendulum clock loses 12s a day if the temperature is 40∘C and gains 4s a day if the temperature is 20∘C. The temperature at which the clock will show correct time, and the co-efficient of linear expansion (α)…2016 · MCQ
  • Consider a spherical shell of radius R at temperature T. The black body radiation inside it can be considered as an ideal gas of photons with internal energy per unit volume u=VU​∝T4 and pressure p=31​(VU​)…2015 · MCQ
  • Consider an ideal gas confined in an isolated closed chamber. As the gas undergoes an adiabatic expansion, the average time of collision between molecules increases as Vq, where V is the volume of the gas. The value of q is: (γ=Cv​Cp​​)…2015 · MCQ
  • A solid body of constant heat capacity 1J/∘C is being heated by keeping it in contact with reservoirs in two ways: (i) Sequentially keeping in contact with 2 reservoirs such that each reservoir supplies…2015 · MCQ