Why the bottom of a cooking vessel in made black ?

Define a black body.

What is the absorption co-efficient of a black body ?

What is the absorptive power of a perfectly black body ?

A solid ball, a solid cylinder roll down a slope which reaches the bottom first ? Which reaches last ? Why?

Why the upper surface of wings of an aero plane are made convex upward and lower concave downwards ?

A vessel has nitrogen gas and water vapours at a total pressure of 1 atm. The partial pressure of water vapours is 0.3 atm. The contents of this vessel are transferred to another vessel havig one third of the capacity of original volume, completely at the same temperature, the total pressure of the system in the new vessel is :

Explain why cooking utensils are always kept black at bottoms and shining at the top.

Why constant of proportionality in second law motion made unity?