Physics Heat 20

yuet

2009-11-08 12:50 am

In an experiment to determine the specific heat capacity of aluminium, an aluminium block of mass 1.7 kg at 20 degree Celsius is heated up by 65W electric heater.The experiment result is 983J/kg degree Celsius . This result is greater than the standard value 870 J/kg degree Celsius. If the difference is solely due to energy loss to the surrounding, calculate the energy lost in 8 minutes.

** As there is a graph in the question, some information may me missing, pls ues symbol to represent it. I don't know is there are missing infomation or not!
THXXXX!!!

回答 (1)

天同

2009-11-08 1:19 am

✔ 最佳答案

Energy supplied by the heater in 8 minutes
= 65 x (8 x 60) J = 31200 J

Hence, 31200 = 1.7 x 983 x (T-20)
where T is the temperature reached in 8 minutes
solve for T gives T = 38.67'C

Let Q be the amount of heat lost to the surroundings in 8 minutes, the heat balance equation is:

31200 = 1.7x 870 x (38.67-20) + Q
i.e. Q = 3590 J

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