InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
What would be the final temperature of a mixture of 50g of water at 20°Ctemperature and 50g of water at 40°C temperature. |
|
Answer» 50 gms water at 20 ⁰ C and 50 gms of water at 40⁰ C are mixed. Since the masses of the liquid at different temperatures are same, the answer is very easy and simple : average of 20⁰C and 40⁰C. that is: 30⁰C.=====================final temperature of the mixture = = [ m1 * T1 + m2 * T2 ] / (m1 + m2) = [ 50 gms * 20⁰ C + 50 gms * 40⁰C ] / (50+50) = 3,000 / 100 = 30⁰C ====================another way using specific heats : let the final temperature be = T ⁰C Amount of heat given out by the hot water = m * s * (40⁰C - T) = 50 gms * s* (40 -T) Amount of heat taken in by the cold water = m * s * (T - 20⁰C) = 50 gms * s * (T - 20 ) As the amounts are equal, because the heat is transferred from hotwater to the cold water without any loss of heat to any surroundings, 50 * s * (40 -T) = 50 gm * s * (T-20) 40 - T = T - 20 2 T = 60 => T = 30⁰C============================= |
|