metal resistance of electricity

👨🏻‍🏫 學術台化學

A student

2008-05-31 8:16 am

When temperature increases, the current of a metal decreases. Why? Is it correct to say that the bonds or sea of electrons are/is easier to become loose because of incease motion of electrons when the temperature increases? If it is correct, then why the current decreases? Shouldn't it be increasing? Since the electrons are more active, then they are easier to move around. And a current is when electrons move in a direction. So increase in temperature helps to increase the activity of the electrons, and therefore increases the current. Am I not right?

更新1:

But the bond weakens as the temperature increases. And the bonds are made up of electrons. So the attraction between the electrons and the nucleus decreases. And because of this, the electrons are less attracted to the nucleus. Right? So they are moving more freely?

回答 (2)

Uncle Michael

2008-05-31 8:52 am

✔ 最佳答案

When a metal conducts electricity, the delocalized electrons move along the direction the electric field applied.

When temperature increases, the metal atoms vibrate to a greater extent. This makes the delocalized electrons more difficult to flow along the metal wire. Therefore, the resistance of the metal wire is increased.

Ohm’s law states that: Current = Voltage/Resistance.
When voltage is kept constant, the current is decreases as the increase in resistance.

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pal cat

2008-06-02 8:57 am

a substance couduct electricity by flow of electon from -ve side to +ve side.
as electrons have greater vibrations upon high temperature, it will be more difficult to 'force' them to move in a certain direction.

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