# Where does the formula I = -e/T comes from?

• I
• Syazani Zulkhairi
In summary, the formula I = -e/T comes from the relationship between current (I), charge (e), and time (T) in the context of electrical circuits. It is derived from Ohm's law and is used to calculate the current in a circuit based on the charge and time. The negative sign indicates the direction of current flow, which is opposite to the direction of electron flow. This formula is fundamental in understanding and analyzing electrical circuits.
Syazani Zulkhairi
Yeah, where does it comes from?

You will have to be more specific and provide context.

In that case, electric current is defined to be the rate of charge passing a particular point.

Charge is given the symbol Q, time t. So if the rate is constant, the current I = Q/t.

In terms of your equation, -e is the charge of one electron, so your current would represent the rate at which a single electron (or something with that amount of charge) passes a particular point.

## 1. What does the formula I = -e/T represent?

The formula I = -e/T represents the relationship between the current (I) flowing through a material and the temperature (T) of that material. It is known as the thermionic emission equation and is used to describe the flow of electrons from a heated surface.

## 2. Where did this formula originate from?

This formula was first proposed by the scientist J.J. Thomson in 1906. He was studying the behavior of electrons in a vacuum, and through his experiments, he discovered that the current flowing through a material is inversely proportional to its temperature.

## 3. How is this formula derived?

The formula I = -e/T can be derived from the principle of thermionic emission, which states that electrons can be emitted from a heated surface. By applying the laws of thermodynamics and quantum mechanics, the equation can be derived to describe the relationship between the current and temperature of a material.

## 4. Is this formula applicable to all materials?

No, this formula is only applicable to materials that exhibit thermionic emission, meaning they release electrons when heated. This includes metals, semiconductors, and certain gases. Other materials, such as insulators, do not follow this relationship.

## 5. Are there any limitations to this formula?

Yes, there are some limitations to this formula. It assumes that the material is in a vacuum and that the temperature is constant. In reality, there may be other factors that can affect the current, such as impurities in the material or changes in the temperature. Additionally, this formula only applies to steady-state conditions and may not accurately predict the behavior of the material under transient conditions.

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