Chapter 4, Problem 70P

For heat transfer purposes, an egg can be considered to be a 5.5-cm- diameter sphere having the properties of water. An egg that is initially at 4.3°C is dropped into boiling water at 100°C. The heat transfer coefficient at the surface of the egg is estimated to be $800W/m^2\cdot K$. If the egg is considered cooked when its center temperature reaches 71°C, determine how long the egg should be kept in the boiling water. Solve this problem using the analytical one-term approximation method.