Q. 11.20 A body cools from to in 5 minutes. Calculate the time it takes to cool from to The temperature of the surroundings is
Let a body initially be at temperature T1
Let its final Temperature be T2
Let the surrounding temperature be T0
Let the temperature change in time t.
According to Newton's Law of cooling
where K is a constant.
We have been given that the body cools from 80 oC to 50 oC in 5 minutes when the surrounding temperature is 20 oC.
T2 = 50 oC
T1 = 80 oC
T0 = 20 oC
t = 5 min = 300 s.
For T1 = 60 oC and T2 = 30 oC we have
The body will take 10 minutes to cool from 60 oC to 30 oC at the surrounding temperature of 20 oC.
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