Question

Four containers are filled with warm water and are allowed to cool on the kitchen counter. Heat losses due to conduction through the bottom and due to natural convection are negligible. Which container cools the fastest?

A. shiny metal
B. dull metal
C. dull black
D. shiny black

Answer 1

The dull black container cools the fastest due to its excellent heat radiation emission capability.

Step-by-step explanation:

The question concerns the rate at which different containers cool down when filled with warm water and left on a kitchen counter. Given that heat losses due to conduction and natural convection are negligible, the cooling rate primarily depends on radiation. Materials with dull and dark surfaces are known to emit radiation more effectively than shiny and light-colored surfaces. Thus, a dull black container would cool the fastest because black surfaces are excellent emitters of heat radiation, and the dull finish increases the effective surface area for radiation.