If I have Volts, and I need eV, how do I get that?

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Homework Help Overview

The discussion revolves around the relationship between volts and electron-volts (eV), specifically addressing how to interpret and convert between these units in the context of energy and potential difference.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster questions whether volts and eV are equivalent, expressing uncertainty about the conversion between these units. Some participants clarify that eV is a unit of energy related to the kinetic energy of an electron accelerated through a voltage.

Discussion Status

Participants are exploring the definitions and relationships between volts and eV, with some providing clarifications about the nature of energy and potential difference. There is an acknowledgment of the original poster's confusion, and further insights into the context of eV in relation to energy measurements are being discussed.

Contextual Notes

Participants mention the work function of metals and the photoelectric effect as relevant contexts where eV is commonly used, indicating that these concepts may influence the understanding of the original question.

April30
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If I have Volts, and I need eV, how do I get that?

Is eV (energy format) = V (voltage format), so that if I have a value given in volts, I know that it would be the same in eV units?

I know this is a dumb question, sorry guys...:blushing:
 
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eV is a unit of energy. It is exactly the amount of kineitic energy that one electron would obtain if it accelerated across one volt of potential difference. You do not convert eV to volts. You convert eV to joules.

Since potential difference is defined as the energy per unit charge ratio you will get a unit of energy when you multiply a unit of charge times a unit of potential, hence "electron-Volt"; here the charge is the fundamental charge of the electron. A joule (unit of energy) is equivalent to a "coulomb-volt." Since 1.602 x 10^-19 coulombs is the charge of an electron, then 1eV = 1.602x10^-19 joules.
 
Thanks Chi,

yeah I suppose I will simply look at eV as the work function of a metal. i just had a mental block ;)
 
April30 said:
Thanks Chi,
yeah I suppose I will simply look at eV as the work function of a metal. i just had a mental block ;)
The work function of a metal is an amount of energy. Any amount of energy can be expressed in eV. When doing the photoelectric effect, the energy of the photon is also measured in eV, and the maximum KE of the electron is again measured in eV. Any of these amounts of energy could just as well be measured in joules, kilowatt-hours, ergs, or any other unit of energy. The eV just happens to be an appropriately small unit of energy.
 

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