# Conversion- MeV to V?

1. May 17, 2005

### lightuplightup

Hello- is it possible to convert MeV to V???? If so, how is it done? For example if a particle is emmitted with an energy of 4.19MeV- how can this be changed into V???? Any help is greatly appreciated.

2. May 17, 2005

### Pengwuino

They are not teh same unit of measure. eV is a unit of energy (1.602 x 10^19 ev = 1 Joule) and V is electrical potential. I think my intro to modern physics said its the energy required to move an electron through a 1 volt potential

3. May 17, 2005

### Staff: Mentor

Is it possible to convert apples to oranges? The MeV (mega-electron-volt) is a unit of energy. The V (volt) is a unit of electrical potential difference.

The volt and the electron-volt are related in that if you take a particle that has a charge equal in magnitude to that on an electron (1.6e-19 coulomb) and accelerate or decelerate it by sending it through a potential difference of one volt, it will gain or lose one electron-volt of energy (which is just another name for 1.6e-19 J of energy).

You can't change the 4.19 MeV into V because they're different kinds of physical quantities. But you can say that in order to bring the particle to a stop, you'd have to send it through a potential difference of -4.19 MV (megavolts).

4. May 17, 2005

### Pengwuino

Simple newbie mistake. I was wondering how to convert eV to volts too. I saw it as "electron-volts" and "volts" and thought, pff, duh! has to be the same! lol.

5. May 17, 2005

### dextercioby

You may wanna rethink that...

Daniel.

6. May 17, 2005

### Pengwuino

What, whats wrong with that?

7. May 17, 2005

### dextercioby

Everything.

$$1eV\simeq 1.6\cdot 10^{-19}J$$

DO you see the difference...?

Daniel.

8. May 18, 2005

### inha

edited for screwing this up myself too.

Last edited: May 18, 2005
9. May 18, 2005

### Pengwuino

Somehow...thinking if 1.602e^-19 J = 1eV then shouldnt 1.602e^19 eV = 1J... I have yet to do a homework problem or exam problem where i got the answer wrong... maybe its because i was rarely ever asked for an answer in Joules...

10. May 18, 2005

### inha

No. Think about it. What do you divide 1.602e^-19 by to make it equal to 1?

11. May 18, 2005

### juvenal

Need to review your scientific notation.

2E-03 = 0.002

The inverse of 2E-03 is not 2E+03 = 2000

Since 2000 * 0.002 = 4.

12. May 18, 2005

### Pengwuino

Obviously all i thought was "pff, to get 1.602e^-19 to equal 1, you must multiply it by 1.602e^19! ". Just one of those things that for some reason, all your knowledge takes a day off and you think of the most assanine way of converting something.

13. May 18, 2005