Q. A can is taken out from a refrigerator at . The atmospheric temperature is . If is the time taken to heat from to and is the time taken from to , then :

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Solution:

Sir Newton's law of heating states that rate of change of temperature of a object is proportional to the difference in temperatures of the surrounding and the object. In the given cases, when initial temperature of can is , the difference in temperatures of can and surrounding is .
When initial temperature of can is , the difference in temperatures of can and surrounding is therefore the rate of heating will be higher, when temperature difference is i.e. time will be smaller than