Heat Transfer - Engineering

Q1:

A __________ surface has the maximum thermal emissivity out of the following.

A black & smooth

B black & rough

C white & smooth

D white & rough

ANS:B - black & rough

A black and rough surface has the maximum thermal emissivity out of the options provided. Black surfaces are known for their high emissivity, meaning they emit thermal radiation effectively. Rough surfaces also tend to have higher emissivity compared to smooth surfaces because they have more surface area and can emit radiation from multiple angles, increasing the overall emission of thermal radiation. Therefore, the correct option is: black & rough