Why Is the Calculated Wavelength Incorrect in This Hydrogen Atom Problem?

[Suyash Singh]

Homework Statement

Calculate energy of electron in first excited state of hydrogen atom.

Homework Equations

n=2
when i use E=-13.6 (z/n)^2
and then use E=hc/lamda(wavelength)
then wavelength is coming wrong

The Attempt at a Solution

the correct answer is 6.68 armstrong.

 

[Orodruin]

Ångström (not armstrong) is a unit of length, not a unit of energy. It is likely that you are not being asked what you have stated that you are being asked about here. The question is likely what the wavelength of the photon emitted when the electron in the first excited state of hydrogen transits to the ground state. This is not the same thing as the energy in the first excited state.

 

[TSny]

when i use E=-13.6 (z/n)^2
and then use E=hc/lamda(wavelength)
then wavelength is coming wrong

Are you trying to find the deBroglie wavelength of the electron when it is in the first excited state? If so, the formula E = hc/λ is not the correct formula.