Properties Of Solids And Liquids Question 544
Question: Steam at $ 1\text{atm}and100{}^\circ C $ enters a radiator & leaves as water at $ 1\text{atm}and80{}^\circ C, $ take $ L _{y}=540\text{ cal/cm} $ and $ s _{water}=11cal/gm/{}^\circ C. $ If the total energy given off as heat, the % age arises from the cooling of water is
Options:
A) 100
B) 54
C) 3.6
D) 8.2
Show Answer
Answer:
Correct Answer: C
Solution:
Let m is the amount of steam that passes off the radiator.
Heat released due to condensation of steam, $ H _{1}=mL _{v}=540mcal $
Heat released due to cooling of water,
$ H _{2}=ms\Delta \theta =m\times 1\times 20=20mcal $
Required percentage
$ =\frac{H _{2}}{H _{1}+H _{2}}\times 100=\frac{20m}{560m}\times 100=3.6% $
