Properties Of Solids And Liquids Question 113
Question: In an industrial process 10 kg of water per hour is to be heated from 20°C to 80°C. To do this steam at 150°C is passed from a boiler into a copper coil immersed in water. The steam condenses in the coil and is returned to the boiler as water at 90°C. how many kg of steam is required per hour. (Specific heat of steam = 1 calorie per gm°C, Latent heat of vaporisation = 540 cal/gm)
Options:
A) 1 gm
B) 1 kg
C) 10 gm
D) 10 kg
Show Answer
Answer:
Correct Answer: B
Solution:
Suppose m kg steam required per hour Heat released by steam in following three steps (i)
When 150°C steam
When 150°C steam
When 100°C water
Heat taken by 10 kg water
Hence Q = Q¢
therefore 600 m = 600 ´ 103
therefore m = 103 gm = 1kg.
