
44 Heat Transfer: Thermal Management of Electronics
PROBLEMS
3.1 Using a simple drawing explain the principle of conservation of energy
for a closed system.
3.2 What is a control mass? What is a control volume? Give three exam-
ples for each.
3.3 What is the appropriate form of energy balance for a surface?
3.4 A 2 kg copper block, initially at 100°C, is brought in contact with a 2 kg
plastic block, initially at 20°C. They are kept in contact long enough to
reach the same equilibrium temperature. The specic heat of plastic is
four times as much as the specic heat of copper. Which block will go
through a larger temperature change? W ...