The energy difference between the two laser levels is 0.275 eV. What is the frequency of the radiation emitted by this laser?

Question

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Answer 1

Hi 

Given E= 0.275 eV = 0.275 *1.6*10^-19 J =  0.44 * 10 ^-19 J ( Converting eV into J , as 1eV = 1.6 * 10 ^-19 J)

 

Now using E = h* frequency 

Frequency = 0.44* 10^-19 / h ( Where h= Planks Constant in JS) Use h= 6.62 * 10 ^-34 Js

 

Frequency  = 0.44* 10^-19/ 6.62* 10^-34 Hz = 0.0664 * 10¹⁵Hz = 6.64 * 10 ¹³ Hz

Answer 2

Hi Kira!

 

Laser light is created by electrons falling from one energy level to another in the atoms of a lasing material.  The difference in energy between the two levels equals the energy of the radiation emitted by the electron as it falls (the energy it is losing by falling to the lower level is being emitted as electromagnetic radiation).

 

Energy of electromagnetic radiation is related to frequency by:

 

E = hf

 

where

 

E = energy of the radiation

f = frequency of the radiation

h = Planck's constant

 

If you put in 0.275 eV as the energy, and use the value for Planck's constant suitable for the eV unit of energy (I believe this is h = 4.14 x 10^-15 eV·s, but you should check this), you can then solve for the frequency (in Hz).

 

I hope this helps!  If you would like to talk further about this, or have any questions -- or want to check an answer -- just let me know.