# How to convert this into eV

• leonne
In summary, the conversation was about finding the energy levels of an electron in an infinite potential box and how to use fundamental constants to make the calculations faster. The solution involves converting between Joules and eV and using combinations of constants to form the correct units for the energy formula.

## Homework Statement

well the problem is electron moving in an infinite poentail box of dimensions... calc all posible energy level in (eV)

## Homework Equations

E=h2/8M(nx2/a2+...

## The Attempt at a Solution

ok so no idea how they get h2/8M to = 37.6 h is planks constant the units are in m4kg s-2 but eV is in m2kg s-2 don't see how they get 37.6 for mass i used 9.11e-31

Find out the energy levels in Joules and simply use the conversion between Joules and eV. Should be easily google'd/wikipedia'ed or should be in your textbook.

There are some useful combinations of the fundamental constants. If you know them, you can make calculations a lot faster.
\begin{align*}
h c &= 1240~\text{eV nm} \\
\hbar c &= 197~\text{eV nm} = 197~\text{MeV fm} \\
m_e c^2 &= 511000~\text{eV} = 511~\text{keV} = 0.511~\text{MeV}
\end{align*}
For your problem, you just need to introduce factors of c, the speed of light, to form the right combinations:
$$\frac{h^2}{8m} = \frac{(hc)^2}{8mc^2} = 0.376~\text{eV nm}^2$$Note that this combination has two powers of length. They are needed to cancel the units from a2 in the denominator of the formula for the energy.

## 1. What is the conversion factor for converting energy units to electron volts (eV)?

The conversion factor for converting energy units to electron volts is approximately 1 eV = 1.602 x 10^-19 joules.

## 2. How do I convert from kilojoules (kJ) to electron volts (eV)?

To convert from kilojoules to electron volts, multiply the number of kilojoules by 6.242 x 10^21. For example, if you have 5 kJ, the conversion would be 5 x 6.242 x 10^21 = 3.121 x 10^22 eV.

## 3. Is there a difference between electron volts (eV) and electronvolts (eV)?

No, electron volts and electronvolts are just two different ways of writing the same unit of energy. They both refer to the amount of energy gained by an electron when it is accelerated through a potential difference of one volt.

## 4. Can I convert from electron volts (eV) to other energy units?

Yes, electron volts can be converted to other energy units such as joules, calories, and kilowatt-hours. The conversion factor will depend on the specific unit you are converting to. For example, to convert from eV to joules, you would multiply by 1.602 x 10^-19. It is important to note that electron volts are commonly used in particle physics and atomic and molecular physics, so they may not be as useful for everyday energy conversions.

## 5. Why do we use electron volts (eV) as a unit of energy in scientific research?

Electron volts are commonly used in scientific research because they are a convenient unit for measuring the energy of subatomic particles. They are also useful for describing the energy levels of atoms and molecules. Additionally, electron volts are smaller and more manageable numbers compared to other energy units such as joules, making them easier to work with in complex calculations.