# What is the difference in energy between 2

What is the difference in energy between the two levels responsible for the ultraviolet emission line of the magnesium atom at 285.2 nm? By commons: (User:Pumbaa User:Greg Robson) [CC BY-SA 2.0 uk], via Wikimedia Commons

#### Solution:

We will first figure out the frequency, and use that value to calculate the difference in energy.

The first equation we will use is:

$v\,=\,\dfrac{c}{\lambda}$

(Where $v$ is frequency, $c$ is speed of light, and $\lambda$ is wavelength)

The question states that the line of emission for the magnesium atom is at 285.2 nm. We will write this value in meters.

$285.2$ nm = $2.852 \times 10^{-7}$ m

Let us substitute the values into our equation to figure out the frequency.

$v\,=\,\dfrac{2.998 \times 10^8 \text{m/s}}{2.852 \times 10^{-7}\text{m}}$

(The speed of light is equal to $2.998 \times 10^8$ m/s)

$v\,=\,1.05 \times 10^{15}$ /s

We will now use the following formula to figure out the energy.

$E\,=\,hv$

(Where $E$ is energy, $h$ is the Planck’s constant, and $v$ is the frequency)

$E\,=\,(6.626\times 10^{-34}\text{J}\cdot \text{s})(1.05 \times 10^{15}\text{/s})$

$E\,=\,6.96\times 10^{-19}$ J

The difference in energy is $6.96\times 10^{-19}$ J

## 2 thoughts on “What is the difference in energy between”

• Thabo

Wow this is great guys

• questionsolutions Post author