Question

Sphere of color black, red, white, and yellow are heated to the same temperature. The decreasing order of cooling is:

• A. \(Black > Red > Yellow > White\)
• B. \(Red > Black > White > Yellow\)
• C. \(White > Yellow > Red > Black\)
• D. \(Yellow > White > Red > Black\)

Hint:

Higher emissivity results in faster cooling. Black surfaces have the highest emissivity.

Answer 1

The Correct Option is A

The cooling of an object depends on its emissivity. The black surface has the highest emissivity, allowing it to radiate heat more efficiently than other colors. The order of cooling (from highest to lowest) is: \[ \text{Black} > \text{Red} > \text{Yellow} > \text{White}. \]