A piece of metal of mass 50g is cooled from 80oC to 20oC. Calculate the amount of heat lost. (specific heat capacity of the material of metal = 450Jkg-1K-1)
A
4.50 x 103J
B
2.25 x 103J
C
1.80 x 103J
D
1.35 x 103J
Verified Correct Answer: D.
Physical Principles & Numerical Solution
mass of metal = 50g = 0.05kg, c = 45Jkg\(^{-1}\)k\(^{-1}\), \DeltaT = 80 - 20 = 60ºC
Quantity of heat lost(Q) = mass of metal x specific capacity of mass x change in temperature
Q = m x c x \DeltaT
Q = 0.05 x 45 x 60 = 1350J = 1.35 x 10\(^3\)J
Source: Myschool Past Questions Archive (Record #33795)