A cup of hot chocolate has temperature 80 ° C in a roomkept at 20 ° C. After half an hour the hot chocolate cools to 60 ° C.(a) What is the temperature of the chocolate after anotherhalf hour?(b) When will the chocolate have cooled to 40 ° C?

A cup of hot chocolate has temperature 80 ° C in a roomkept at 20 ° C. After half an hour the hot chocolate cools to 60 ° C.(a) What is the temperature of the chocolate after anotherhalf hour?(b) When will the chocolate have cooled to 40 ° C?

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.39P: The tip of a soldering iron consists of a 0.6-cm- diameter copper rod, 7.6 cm long. If the tip must...

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Concept explainers

Mechanisms of heat transfer

Heat transfer is an essential discipline in thermal engineering that deals with the transfer, conversion, usability, and creation of heat or thermal energy. Transfer of heat occurs through various mechanisms like conduction, convection, radiation, and change of phases. All these mechanisms have distinct characteristics, but these mechanisms can simultaneously occur in an identical system.

Question

A cup of hot chocolate has temperature 80 ° C
in a room
kept at 20 ° C
. After half an hour the hot chocolate cools to 60 ° C

.
(a) What is the temperature of the chocolate after another
half hour?
(b) When will the chocolate have cooled to 40 ° C
?

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