Wednesday, February 10, 2010

The rate of melting depends on the amount of thermal energy present. True or False, why ?

True. You mean if I put an ice cube in the oven it will melt faster than if in the freezer?





The amount of energy transfered is proportional to the surface area and difference in the surrounding temp and the objects temp. More area means more ways to transfer energy. A higher temp means more energy. By the way, average thermal energy kinda is temperature.





If the object doesn't affect the ambient temperature (say an ice cube in a large room) then (and remember that for a particular phase, say ice, the temperature is constant) then the difference between the object and it's surrounding does not change. However, it's surface area melts away, and so it's rate of cooling slows.





So, for an ice cube in a large room (constant ambient temperature) the surface area affects the rate of cooling and not the thermal energy present.





The answer can be either true or false. It's one of those ambiguous types.The rate of melting depends on the amount of thermal energy present. True or False, why ?
This is very true.


You can put a frozed object in a glass of warm water and it will take X amount of time.





The same object put in a saucepan on the stove(turned on high) and the time will be some fraction of X.





So we can conclude that the two are inversely related. As the heat increases the time decreases, or as heat increases so does the rate of melt.The rate of melting depends on the amount of thermal energy present. True or False, why ?
True, the higher the thermal energy available, the faster the heat transfer rate, the faster the melting will take place.

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