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Physics chapters

Thermal Properties of Matter

8 JEE Main questions · Physics

Calorimetry and change of state

  1. PhysicsJEE Main 21 Jan 2026, Shift 1·Q2·MCQ·Easy–moderate
    Open
    A gas based geyser heats water flowing at the rate of 5.0 litres per minute from 27∘27^\circC to 87∘87^\circC. The rate of consumption of the gas is g/s. (Take heat of combustion of gas =5.0×104= 5.0\times10^{4} J/g) specific heat capacity of water =4200= 4200 J/kg. ∘^\circC
    1. (1)2.1
    2. (2)4.2
    3. (3)0.42
    4. (4)0.21
  2. PhysicsJEE Main 28 Jan 2026, Shift 1·Q1·MCQ·Moderate
    Open
    10 kg of ice at −10∘-10^\circC is added to 100 kg of water to lower its temperature from 25∘25^\circC. Consider no heat exchange to surroundings. The decrement to the temperature of water is ∘^\circC.
    (specific heat of ice =2100= 2100 J/kg.∘^\circC, specific heat of water =4200= 4200 J/kg.∘^\circC, latent heat of fusion of ice =3.36×105= 3.36\times10^{5} J/kg)
    1. (1)10
    2. (2)15
    3. (3)6.67
    4. (4)11.6
    We corrected a printing error in the original paper

    Source printed the unit as “J/Kg” (three times).

  3. PhysicsJEE Main 28 Jan 2026, Shift 1·Q8·MCQ·Easy–moderate
    Open
    Which of the following best represents the temperature versus heat supplied graph for water, in the range of −20∘-20^\circC to 120∘120^\circC ?
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  4. PhysicsJEE Main 5 Apr 2026, Shift 2·Q22·Numerical·Moderate
    Open
    The heat extracted out of x gram of water initially at 50∘50^\circC to cool it down to 0∘0^\circC is sufficient to evaporate (1000−x)(1000 - x) gram of water also initially at 50∘50^\circC. The value of x (closest integer) is.
    (Take latent heat of water 2256 kJ/kg, specific heat capacity of water 4200 J/kg. K)
    We corrected a printing error in the original paper

    Source printed the latent heat as “2256 kJ/kg. K”.

Temperature and expansion

  1. PhysicsJEE Main 21 Jan 2026, Shift 1·Q15·MCQ·Easy–moderate
    Open
    Aluminium and steel rods having same lengths and cross-sections are joined to make total length of 120 cm at 30∘30^\circC. The coefficients of linear expansion of aluminium and steel are 24×10−6/∘24\times10^{-6}/^\circC and 1.2×10−5/∘1.2\times10^{-5}/^\circC, respectively. The length of this composite rod when its temperature is raised to 100∘100^\circC, is cm.
    1. (1)120.20
    2. (2)120.15
    3. (3)120.03
    4. (4)120.06
    We corrected a printing error in the original paper

    Source printed “An aluminium and steel rods” and “The coefficient of linear expansion … are”.

  2. PhysicsJEE Main 24 Jan 2026, Shift 1·Q14·MCQ·Easy–moderate
    Open
    A brass wire of length 2 m and radius 1 mm at 27∘27^\circC is held taut between two rigid supports. Initially it was cooled to a temperature of −43∘-43^\circC creating a tension TT in the wire. The temperature to which the wire has to be cooled in order to increase the tension in it to 1.4T1.4T, is ∘^\circC
    1. (1)−86-86
    2. (2)−71-71
    3. (3)−65-65
    4. (4)−80-80
  3. PhysicsJEE Main 4 Apr 2026, Shift 2·Q9·MCQ·Moderate
    Open

    The temperature of a metal strip having coefficient of linear expansion α\alpha is increased from T1T_1 to T2T_2 resulting in increase of its length by ΔL1\Delta L_1. The temperature is further increased from T2T_2 to T3T_3 such that the increase in its length is ΔL2\Delta L_2.

    Given T3+T1=2T2T_3 + T_1 = 2T_2 and T2−T1=ΔTT_2 - T_1 = \Delta T, the value of ΔL2\Delta L_2 is .

    1. (1)ΔL1[1+2α2(ΔT)2]\Delta L_1[1 + 2\alpha^2(\Delta T)^2]
    2. (2)ΔL1[1+α2(ΔT)2]\Delta L_1[1 + \alpha^2(\Delta T)^2]
    3. (3)ΔL1[1+2α ΔT]\Delta L_1[1 + 2\alpha\,\Delta T]
    4. (4)ΔL1[1+α ΔT]\Delta L_1[1 + \alpha\,\Delta T]

Heat transfer

  1. PhysicsJEE Main 22 Jan 2026, Shift 1·Q13·MCQ·Moderate
    Open
    Rods x and y of equal dimensions but of different materials are joined as shown in figure. Temperatures of end points AA and FF are maintained at 100 ∘100\ ^\circC and 40 ∘40\ ^\circC respectively. Given the thermal conductivity of rod x is three times of that of rod y, the temperatures at junction points BB and EE are (close to):
    1. (1)89 ∘89\ ^\circC and 73 ∘73\ ^\circC respectively
    2. (2)80 ∘80\ ^\circC and 60 ∘60\ ^\circC respectively
    3. (3)80 ∘80\ ^\circC and 70 ∘70\ ^\circC respectively
    4. (4)60 ∘60\ ^\circC and 45 ∘45\ ^\circC respectively
    We corrected a printing error in the original paper

    Source printed “the temperature at junction points BB and EE are”.