NEET Solved Paper 2014 Question 15

Question: Steam at $ 100^{o}C $ is passed into 20 g of water at $ 10^{o}C $ . When water acquires a temperature of $ 80^{o}C $ , the mass of water present will be [Take specific heat of water = $ 1,cal{g^{-1}}{{,}^{{}^\circ }}{C^{-1}} $ and latent heat of steam $ =540cal{g^{-1}}] $ [AIPMT 2014]

Options:

A) 24g

B) 31.5g

C) 42.5g

D) 22.5g

Show Answer

Answer:

Correct Answer: D

Solution:

  • Heat lost by steam = Heat gained by water Let M? amount of heat converts into water. $ m’\times L=ms,\Delta t $ $ m’\times 540=20\times 1\times (80-10) $ $ m’=\frac{20\times 70}{540}=2.5g $ Now, net water = 20 + 2.5 = 22.5g