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ymgoh95

2012-11-16 03:54 PM

What is the final temperature when 100g of water at 25'c is mixed with 75g of water at 50'c

ymgoh95

2012-11-16 04:07 PM

A voltmeter reading is 1.5V when the switches opened.The voltmeter reading drops to 1.35V when a bulb is connected to the battery meter reading is 0.3A.

What is the internal resistance of the battery?.

warriorwj

2012-11-16 04:29 PM

我在想你在这里问会有人回答你吗？
那个internal resistance is using the V=IR formula.
the temperature is using the energy formula (energy lost = energy gain)

P2PSYSTEM

2012-11-16 04:44 PM

回复 1# ymgoh95

0.1 x 4200 x 25 + 0.075 x 4200 x 50= 0.175 x 4200 x T
T=35.71

1.5-1.35=0.3r
r=0.5

ymgoh95

2012-11-16 06:32 PM

回复 4# P2PSYSTEM

谢谢咯～今年中5？

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