Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for_________________?

Question

Accepted Answer

Cube. The object with the largest surface area to volume ratio cools fastest. For equal mass and dimensions like this, the cube has the highest surface area to volume ratio.