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Water of mass \(m\) gram is slowly heated to increase the temperature from \({T}_{1}\) to \({T}_{2}\). The change in ent…

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Water of mass \(m\) gram is slowly heated to increase the temperature from \({T}_{1}\) to \({T}_{2}\). The change in entropy of the water, given specific heat of water is \(1{\mathrm{Jkg}}^{-1}{\mathrm{K}}^{-1}\), is :

[JEE Main 2025, 23 Jan (Shift 2)]

a

\(\mathrm{mln}\left(\frac{{\mathrm{T}}_{2}}{{\mathrm{T}}_{1}}\right)\)

b

zero

c

\(\mathrm{m}\left({\mathrm{T}}_{2}-{\mathrm{T}}_{1}\right)\)

d

\(\mathrm{mln}\left(\frac{{\mathrm{T}}_{1}}{{\mathrm{T}}_{2}}\right)\)

✓ Correct answer: a)

\(\mathrm{mln}\left(\frac{{\mathrm{T}}_{2}}{{\mathrm{T}}_{1}}\right)\)

Explanation

\(I=dQ\\ dQ=TdS\\ dS=\frac{dQ}{T}\\ \int dS={\int }_{{T}_{1}}^{T}mC\frac{dT}{T}\\ \Delta S=mC[\ln T{]}_{{T}_{1}}^{{T}_{2}}\)

\(\Delta S=mC\ln \frac{{T}_{2}}{{T}_{1}}\)

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