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QNEET-2021-Ph-619: NEET 2021 Physics - Class 11 NEET-2021-Ph-619 Solution: A cup of coffee cools from $90^ C$ to $80^ C$ in t minutes…

A cup of coffee cools from

90^\circ C

80^\circ C

in t minutes when the room temperature is

20^\circ C

. The time taken by a similar cup of coffee to cool from

80^\circ C

60^\circ C

at a room temperature same at

20^\circ C

is:

\frac{5}{13}t

\frac{13}{10}t

\frac{13}{5}t

\frac{10}{13}t

Step-by-Step Verified Solution

d T d t = K ( T a v _ T 0 ) 10 t = K ( 85 _ 20 ) 20 t = K ( 70 _ 20 ) t _ 2 t = 65 50 t _ t = 130 50 t _ = 13 5 t