Question

why is some of the cooking vessels ,the base is painted black?

Answer 1

some cooking vessels , the base is black bcaz it's not sticky.. and the food does not get burnt

Answer 2

All hot objects -solid, liquid or gas-emit radiant energy. Radiant heat travels in the same way  as light. In fact, it travels at the same speed. When light falls on an object, it is partially  absorbed and partially reflected. The extent of absorption and reflection of radiant heat  depends upon: The nature of the surface it has and the colour of the object.  Shiny and smooth surfaces reflect heat better while dark and rough surfaces absorb heat better. That is why cooking vessel is painted black so it can absorb heat nicely.