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I have just started learning physics, and am very confused with Ohm's Law.

Ohm's Law states that the electrical current flowing in a metallic conductor is directly proportional to the potential energy applied across its ends, given that the physical conditions are kept constant.

It is my understanding that current refers to the number of charges flowing through a certain point of the circuit per second. Potential energy refers to the work done to drive one coulomb of electrons through an electronic component, or the amount of electrical energy converted to other forms of energy when one coulomb of electrons passes through an electronic component.

So my question is, how is it that when the resistance of a metallic conductor is kept constant, the greater the number of charges flowing through the component in one second, the greater the amount of energy required to drive one charge through that component?

Is there a reason behind it, or does it just happen like that?

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    $\begingroup$ Key: electrical potential difference and electrical potential energy are not exactly the same thing. $\endgroup$ – The Photon Apr 9 '17 at 19:24
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The more electrons attracted the more kinetic energy endorsed to them and so the greater the potential energy difference. You can see it like a mechanics problem. The more mass I have to move the more energy I have to spend.

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I added this illustration to another answer some time ago, for an intuitive picture.

Potential difference acts just like pressure difference in a water pipe (and the flow of water corresponds to the current); the larger the pressure, the faster the water moves. And the other way around: the faster the water moves, the larger the pressure must be (otherwise it wouldn't move faster).

An increase in current means that a larger "push" in the form of larger potential difference must be present.


A sidenote, rather than saying number of charges flowing per second, you should be saying amount of charge flowing per second.

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Current is the amount of charges that pass a certain cross area in a certain time. When electrons pass through the resistor, they collide a lot thus there is a potential drop that is converted to heat and light. So the answer is as the current increases, more collisions will happen thus more energy is converted to another form of energy.

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