Energy of a photon emission or absorbtion

[DODGEVIPER13]

Homework Statement

When energy is absorbed is the E value negative and when the energy is emitted is the E value positive?

Homework Equations

E=hf=E1-E2 (Is this equation correct for noth emision and absorbtion or just absorbtionbecause this is what my textbook says)
E=-13.6/n^2

The Attempt at a Solution

I realize that when an electron drops from a excited state, the electron emits EM radiation. In the reverse process the electron absorbs energy. So if I use the equations I provided above I would always get a negative number and it also would make it look like energy absorbtion. However if I reverse the equation and make it look similar to the others I have found online E=hf=E2-E1 and apply the second equation to it I will get a positive number,and it will emit. So my question is does the equation alternate when looking at absorbtion and emission, if not is the equation in my book wrong and if its not then is my therory correct that negative means absorbtion and positive means emission.

 

[mark726]

Thank you for your question about the relationship between energy absorption and emission. The equation you provided, E=hf=E1-E2, is correct for both absorption and emission processes. This equation shows the relationship between the energy of a photon (E), its frequency (f), and the energy levels (E1 and E2) of the atom or molecule involved in the process.

In terms of the sign of the energy value, it is important to remember that energy is a scalar quantity and does not have a positive or negative direction. The negative sign in the equation E=-13.6/n^2 simply indicates that the energy of the electron is decreasing as it moves from a higher energy level to a lower energy level. Similarly, the positive sign in the equation E=hf=E1-E2 indicates that the energy of the photon is increasing as it is emitted from the atom or molecule.

In summary, the sign of the energy value does not indicate whether it is absorption or emission, but rather the direction of the energy transfer. I hope this helps clarify any confusion you may have had. If you have any further questions, please don't hesitate to ask.