What is the energy of a photon released by an electron going from the first excited energy (n=2) level to ground state (n=1). note: e1 = -13.6ev. e2 = -3.4ev. what is the wavelength, frequency, and speed of the photon in a vacuum?

E= 10.2 ev

Explanation:

It is given that energy in first exited state (n=2) , = -3.4 ev

Also , it is given than energy in ground state (n=1) , = -13.6 ev.

We know energy of photon released is difference of the final and initial level of electron.

Energy of photon released,  

Therefore, .

To convert energy from ev(electron volt) into joule we need to multiply energy in ev by charge of electron which is ( )

Therefore,

Now , we know that photon is an quantum of light . Therefore, speed of photon in vaccum is equal to speed of light which is , .

Now, by energy-wavelength relation,

where ,

Now, putting values of h ,c and E in above equation .

We know,

Therefore,

Hence, this is the required solution.

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