A body cools from \[{{50.0}^{o}}C\] to \[{{49.9}^{o}}C\] in \[5\ s\]. How long will it take to cool from \[{{40.0}^{o}}C\] to \[{{39.9}^{o}}C\]? Assume the temperature of surroundings to be \[{{30.0}^{o}}C\] and Newton's law of cooling to be valid [CBSE PMT 1994]

• A.            2.5 s                                         
• B.            10 s
• C.            20 s                                          
• D.            5 s