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[Phy] heat capacity question please help

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heat capacity question please help

q c(1),
why the energy adsorbed will be reduced ge?
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回覆 1# suking2014 的帖子

smaller heat capacity means less energy is needed to increase an unit of temperature.

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1. The rate of heat transfer is directly proportional to the temperature difference
2. When the container has a smaller heat capactiy, even the same amount of energy is inputted,
     the temperature of the container will rise quicker and attain a very similar temperature with the water
     i.e. rate of heat transfer will become very small very quickly
     -->the heat lost to the container will be smaller afterwards.
By the way, please note that adsorb and absorb are two different words with two difference meanings.
6科5**
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但係smaller heat capacity 唔係會increase heat loss to surroundings meh? 就好似發泡膠杯vs鐵杯咁

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引用:
原帖由 suking2014 於 2016-10-9 03:57 PM 發表
但係smaller heat capacity 唔係會increase heat loss to surroundings meh? 就好似發泡膠杯vs鐵杯咁
Firstly, expanded polystyrene cup (發泡膠杯) has a smaller rate of heat loss to surrounding is because it is a poor conductor while metal cup is a good conductor.
(Or you may explain it by the shiny surface of metal cup which gives rise to a better emitter of radiation)

At least in DSE, we do not assume a direct relationship between heat capacity and heat loss to surrounding.

Secondly, the container is put in the oven, where the temperature inside the oven is always higher than the temperature of water
otherwise, water will not gain heat energy.
Therefore, there is no heat loss to surrounding in this case.
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引用:
原帖由 Pockhin 於 2016-10-9 10:04 PM 發表

Firstly, expanded polystyrene cup (發泡膠杯) has a smaller rate of heat loss to surrounding is because it is a poor conductor while metal cup is a good conductor.
(Or you may explain it by the shi ...
thanks,  但係after the beaker being taken out from the oven, 佢要佢要用溫度計量water ge溫度, 咁都要等一段時間先量到waterHfinal temperature (你用溫度計放落100度H水都要等幾十秒 溫度計先會show100C ga ma) , so there is heat loss to surroundings.......

定係條題目assume 溫度計一放啲water 就即刻量到佢Htemperature?

佢嗰實驗步驟係咁H:

[ 本帖最後由 suking2014 於 2016-10-10 05:50 PM 編輯 ]
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引用:
原帖由 suking2014 於 2016-10-10 05:47 PM 發表

thanks,  但係after the beaker being taken out from the oven, 佢要佢要用溫度計量water ge溫度, 咁都要等一段時間先量到waterHfinal temperature (你用溫度計放落100度H水都要等幾十秒 溫度計先會show100C ga ...
Please note that there is no direct relationship between heat capacity and rate of heat loss to the surrounding.
As I havbe mentioned, why a metal cup has a higher rate of heat loss is because of its shiny surface, but not its small heat capacity.
Lowering the heat capacity is not necessarily changing the material being used, like she can use a smaller beaker.
In this case, same material but smaller contact surface area with air-->smaller heat lost to the sorrounding, but it has a smaller heat capacity as its mass decreases.

You are using a wrong concept to derive a wrong conclusion.

Also, we indeed have a practice to ignore the time for measuring the temperature, unless it is specified by the question.
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引用:
原帖由 Pockhin 於 2016-10-11 06:49 PM 發表

Please note that there is no direct relationship between heat capacity and rate of heat loss to the surrounding.
As I havbe mentioned, why a metal cup has a higher rate of heat loss is because of i ...
唔該曬你最尾嗰句! 而家明曬

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