----------功率----------------

HIUWA

2007-06-09 7:08 pm

上面所顯示的是，以100 W的功率向質量為0.4 kg的金屬塊提供熱量時，金屬塊的溫度隨時間而變化的關係線圈。以J kg-1 K-1為單位時，金屬的比熱容是 ? /-\\ T :60-20 t:100s
A. 210。
B. 325。
C. 400。
D. 600。
E. 625。

回答 (1)

Audrey Hepburn

2007-06-09 7:44 pm

✔ 最佳答案

The answer is E. 625.

First of all, find out the total energy supplied by the power source

Energy supply
= Power X time
= 100 X 100
= 10 000 J

Mass of the metal, m = 0.4 kg
Temperature change of the metal, ΔT = 60 - 20 = 40℃

Let c be the specific heat capacity of the metal

Assume no heat is lost to the surroundings,

By the law of conservation of energy,

Energy supply = mcΔT

10 000 = (0.4)c(40)

c = 625 J kg^-1 K^-1

So, specific heat capacity of the metal is 625 J kg^-1 K^-1.

參考: Myself~~~

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