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

2023 · 24 Jan · Shift 1 · 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. /2023 · 24 Jan · Shift 1 · Q55

Heat and Thermodynamics question

2023 · 24 Jan · Shift 1 · Q55

JEE MainPhysicsHeat and ThermodynamicsMCQ+4 / −1
1 g of a liquid is converted to vapour at 3 ×\times× 10 5^55 Pa pressure. If 10% of the heat supplied is used for increasing the volume by 1600 cm 3^33 during this phase change, then the increase in internal energy in the process will be :
  1. A
    4800 J
  2. B
    4320 J
  3. C
    432000 J
  4. D
    4.32 ×\times× 10 8^88 J
View written solutionFree

Correct answer: B

  1. Use the first law of thermodynamics

    During vaporisation at constant pressure, Q=ΔU+WQ = \Delta U + WQ=ΔU+W where:

    • QQQ = heat supplied
    • ΔU\Delta UΔU = increase in internal energy
    • W=PΔVW = P\Delta VW=PΔV = work done in expansion

  2. Given that 10% of the heat is used in expansion work

    So, W=0.1QW = 0.1QW=0.1Q

  3. Calculate the expansion work

    Pressure: P=3×105 PaP = 3 \times 10^5\ \text{Pa}P=3×105 Pa

    Increase in volume: ΔV=1600 cm3=1600×10−6 m3=1.6×10−3 m3\Delta V = 1600\ \text{cm}^3 = 1600 \times 10^{-6}\ \text{m}^3 = 1.6 \times 10^{-3}\ \text{m}^3ΔV=1600 cm3=1600×10−6 m3=1.6×10−3 m3

    Hence, W=PΔV=(3×105)(1.6×10−3)=480 JW = P\Delta V = (3 \times 10^5)(1.6 \times 10^{-3}) = 480\ \text{J}W=PΔV=(3×105)(1.6×10−3)=480 J

  4. Find total heat supplied

    Since W=10%W = 10\%W=10% of QQQ, 0.1Q=4800.1Q = 4800.1Q=480 Q=4800 JQ = 4800\ \text{J}Q=4800 J

  5. Find increase in internal energy

    Using ΔU=Q−W\Delta U = Q - WΔU=Q−W ΔU=4800−480=4320 J\Delta U = 4800 - 480 = 4320\ \text{J}ΔU=4800−480=4320 J

  6. Match with options

    ΔU=4320 J\Delta U = 4320\ \text{J}ΔU=4320 J

    So the correct option is B.

PreviousNext

More from Heat and Thermodynamics

  • Given below are two statements : Statement I : The temperature of a gas is −73∘ C. When the gas is heated to 527∘ C, the root mean square speed of the molecules is doubled. Statement II : The product of pressure and volume of…2023 · MCQ
  • A hole is drilled in a metal sheet. At 27∘C, the diameter of hole is 5 cm. When the sheet is heated to 177∘C, the change in the diameter of hole is d×10−3 cm. The value of d will be ​…2023 · Numerical
  • Let γ1​ be the ratio of molar specific heat at constant pressure and molar specific heat at constant volume of a monoatomic gas and γ2​ be the similar ratio of diatomic gas. Considering the diatomic gas molecule as a rigid…2023 · MCQ
  • In an Isothermal change, the change in pressure and volume of a gas can be represented for three different temperature; T3​>T2​>T1​ as :2023 · MCQ
  • The root mean square velocity of molecules of gas is2023 · MCQ
  • Match List I with List II Choose the correct answer from the options given below : Includes table2023 · MCQ
  • The graph between two temperature scales P and Q is shown in the figure. Between upper fixed point and lower fixed point there are 150 equal divisions of scale P and 100 divisions on scale Q. The relationship for conversion between the two… Includes diagram2023 · MCQ
  • According to law of equipartition of energy the molar specific heat of a diatomic gas at constant volume where the molecule has one additional vibrational mode is :-2023 · MCQ