Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 202523 JanuaryEvening Shift
Exam
JEE Main
Year
2025
Date
23 January
Shift
Evening Shift
Subject
Physics
Chapter
Thermodynamics

JEE Main 2025 · 23 January · Evening Shift · Physics · Thermodynamics

Water of mass m gram is slowly heated to increase the temperature...

Water of mass mm gram is slowly heated to increase the temperature from T1T_1 to TzT_z The change in entropy of the water, given specific heat of water is 1Jkg−1 K−11 \mathrm{Jkg}^{-1} \mathrm{~K}^{-1}, is :

Options

  1. Amln⁡(T2 T1)\mathrm{m} \ln \left(\frac{\mathrm{T}_2}{\mathrm{~T}_1}\right)
  2. Bzero
  3. Cmln⁡(T1 T2)\mathrm{m} \ln \left(\frac{\mathrm{T}_1}{\mathrm{~T}_2}\right)
  4. Dm(T2−T1)\mathrm{m}\left(\mathrm{T}_2-\mathrm{T}_1\right)

Correct answer

A. mln⁡(T2 T1)\mathrm{m} \ln \left(\frac{\mathrm{T}_2}{\mathrm{~T}_1}\right)

Step-by-step solution

dQ=msdTdS=dQT=msdTTΔS=∫msdTT=msln⁡TfTiΔS=mln⁡T2 T1\begin{aligned} & d \mathrm{Q}=\mathrm{msdT} \\ & \mathrm{dS}=\frac{\mathrm{dQ}}{\mathrm{T}}=\frac{\mathrm{msdT}}{\mathrm{T}} \\ & \Delta \mathrm{S}=\int \frac{\mathrm{msdT}}{\mathrm{T}}=\mathrm{ms} \ln \frac{\mathrm{T}_{\mathrm{f}}}{\mathrm{T}_{\mathrm{i}}} \\ & \Delta \mathrm{S}=\mathrm{m} \ln \frac{\mathrm{T}_2}{\mathrm{~T}_1}\end{aligned}
Practice Thermodynamics on Quantrex Academy →

More from Thermodynamics

A quasi-static cycle of a monoatomic ideal gas contains an isothermal process ( ab )… JEE Advanced 2026As shown in the figure, five Carnot engines, each with efficiency η and same number of… JEE Advanced 2026Ten moles of an ideal monoatomic gas, initially in state a at atmospheric pressure and… JEE Advanced 2026One mole of diatomic gas having rotational modes only is kept in a cylinder with a piston… JEE Main 2026Initial pressure and volume of a monoatomic ideal gas are P and V . The change in… JEE Main 2026A cylinder with adiabatic walls is closed at both ends and is divided into two… JEE Main 2026Two closed vessels of same volume are joined through a narrow tube and both vessels are… JEE Main 2026A certain gas is isothermally compressed to ((1)/(3))^ rd of its initial volume ( V_o = 3… JEE Main 2026 Full Thermodynamics list All JEE Main PYQs