Physics Circle home Student Login

Home›Chapters›Thermometry, Thermal Expansion and Calorimetry PYQs›Calorimetry, Latent Heat & Mechanical Equivalent of Heat›Question 49

JEE Main 2013 (22 Apr, Shift 1) · Calorimetry, Latent Heat & Mechanical Equivalent of Heat

Calorimetry, Latent Heat & Mechanical Equivalent of Heat question from JEE Main 2013 (22 Apr, Shift 1)

Q49JEE Main 2013 · 22 APR · SHIFT 1Medium

Calorimetry, Latent Heat & Mechanical Equivalent of Heat

Given that 1 g of water in liquid phase has volume 1 cm3^{3} and in vapour phase 1671 cm3^{3} at atmospheric pressure and the latent heat of vaporization of water is 2256 J/g; the change in the internal energy in joules for 1 g of water at 373 K when it changes from liquid phase to vapour phase at the same temperature is:

Show answer and solution

Answer: (c)

  1. ΔU=Q−PΔV\Delta U = Q - P\Delta V, with Q=2256 JQ = 2256\text{ J}.
  2. PΔV=1.013×105×1670×10−6≈167 JP\Delta V = 1.013 \times 10^5 \times 1670 \times 10^{-6} \approx 167\text{ J}
  3. ΔU=2256−167=2089 J\Delta U = 2256 - 167 = 2089\text{ J}
  4. So the answer is (c) 2089.
Report a mistake

More questions on Calorimetry, Latent Heat & Mechanical Equivalent of Heat