Q.
Steam at 100°C is passed into 20 g of water at 10°C. When water acquires a temperature of 80°C the mass of water present will be : [Take specific heat of water = 1 cal $g^{-1}$ °$C^{-1}$ and latent heat of steam = 540 cal $g^{-1}$]
A) 24 g
B) 31.5 g
C) 42.5 g
D) 22.5 g
Explanation
[Solution] m(540 + 20) = 20 × 70 ⇒ m = 2.5 g of steam condenses; total water = 22.5 g. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.