Question

the bottom of the cooking utensils is painted black while the sides are sparkling bright

Answer 1

Black colour absorbs heat whereas white reflects heat. Bottom of the utensils are painted black so that they could absorb maximum possible heat from below and cook the food early and properly. The sides of cooking utensils are painted sparkling bright so that the contents could get only that much heat from bottom and it doesn't absorb any extra heat from the sides and moreover the inner sides could reflect heat inside rather than absorbing it and passing it to the atmosphere.
Thanks.

Answer 2

$\textbf{Answer is in Attachment !}$