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

2019 · 10 Jan · Shift 2 · Q55
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. /2019 · 10 Jan · Shift 2 · Q55

Heat and Thermodynamics question

2019 · 10 Jan · Shift 2 · Q55

JEE MainPhysicsHeat and ThermodynamicsMCQ+4 / −1
Half mole of an ideal monoatomic gas is heated at constant pressure of 1 atm from 20oC to 90oC. Work done by gas is close to – (Gas constant R = 8.31 J/mol.K)
  1. A
    581 J
  2. B
    73 J
  3. C
    146 J
  4. D
    291 J
View written solutionFree

Correct answer: D

  1. Given data
  • Number of moles: n=12=0.5n = \dfrac{1}{2} = 0.5n=21​=0.5 mol
  • Process: constant pressure
  • Initial temperature: T1=20∘C=293 KT_1 = 20^\circ C = 293\,KT1​=20∘C=293K
  • Final temperature: T2=90∘C=363 KT_2 = 90^\circ C = 363\,KT2​=90∘C=363K
  • Gas constant: R=8.31 J mol−1K−1R = 8.31\,\text{J mol}^{-1}\text{K}^{-1}R=8.31J mol−1K−1

So,

ΔT=T2−T1=363−293=70 K\Delta T = T_2 - T_1 = 363 - 293 = 70\,KΔT=T2​−T1​=363−293=70K
  1. Work done in an isobaric process

For an ideal gas heated at constant pressure,

W=PΔV=nRΔTW = P\Delta V = nR\Delta TW=PΔV=nRΔT

Substitute the values:

W=0.5×8.31×70W = 0.5 \times 8.31 \times 70W=0.5×8.31×70
  1. Calculation

First,

8.31×70=581.78.31 \times 70 = 581.78.31×70=581.7

Then,

W=0.5×581.7=290.85 JW = 0.5 \times 581.7 = 290.85\,JW=0.5×581.7=290.85J

Thus,

W≈291 JW \approx 291\,JW≈291J
  1. Match with options
  • A: 581 J581\,J581J
  • B: 73 J73\,J73J
  • C: 146 J146\,J146J
  • D: 291 J291\,J291J

So the correct option is:

D: 291 J\boxed{\text{D: } 291\,J}D: 291J​
  1. Comparison with stored answer

Stored correct answer is D, and our derived answer is also D.

Hence, they agree.

PreviousNext

More from Heat and Thermodynamics

  • An unknown metal of mass 192 g heated to a temperature of 100oC was immersed into a brass calorimeter of mass 128 g containing 240 g of water at a temperature of 8.4oC. Calculate the specific heat of the unknown metal if water temperature…2019 · MCQ
  • Two kg of a monoatomic gas is at a pressure of 4 × 104 N/m2. The density of the gas is 8 kg/m3. What is the order of energy of the gas due to its thermal motion ?2019 · MCQ
  • Ice at –20oC is added to 50 g of water at 40oC. When the temperature of the mixture reaches 0oC, it is found that 20 g of ice is still unmelted. The amount of ice added to the water was close to (Specific heat of water = 4.2J/g/oC Specific…2019 · MCQ
  • A rigid diatomic ideal gas undergoes an adiabatic process at room temperature. The relation between temperature and volume for this process is TVx = constant, then x is :2019 · MCQ
  • A gas mixture consists of 3 moles of oxygen and 5 moles of argon at temperature T. considering only translational and rotational modes, the total internal energy of the system is :2019 · MCQ
  • A thermometer graduated according to a linear scale reads a value x0 when in contact with boiling water, and x0/3 when in contact with ice. What is the temperature of an object in oC, if this thermometer in the contact with the object…2019 · MCQ
  • A metal ball of mass 0.1 kg is heated upto 500oC and dropped into a vessel of heat capacity 800 JK–1 and containing 0.5 kg water. The initial temperature of water and vessel is 30oC. What is the approximate percentage increment in the…2019 · MCQ
  • When 100 g of a liquid A at 100oC is added to 50 g of a liquid B at temperature 75oC, the temperature of the mixture becomes 90oC. The temperature of the mixture, if 100 g of liquid A at 100oC is added to 50 g of liquid B at 50oC, will be :2019 · MCQ