Step 1: Find the Total Energy (TE) from the Given Potential Energy (PE)
The potential energy of the electron is given as -6.8 eV .
We use the relation:
PE=2(TE)This means:
TE=2PE​=2−6.8​=−3.4 eVStep 2: Find the Value of
n (Principal Quantum Number)
For a hydrogen atom, the total energy formula is:
TE=n2−13.6​Set this equal to the TE we found:
−3.4=n2−13.6​Solve for
n2:n2=4So,
n=2Step 3: The Electron is in the Second Orbit
Since
n=2, the electron is in the second Bohr orbit.
Step 4: Use Bohr's Model and de-Broglie Hypothesis
According to Bohr and de-Broglie:
2πrn​=nλThis gives:
λ=n2πrn​​Step 5: Use the Formula for the Radius of Orbit
Radius of the nth orbit:
rn​=n2r0​For
n=2 (second orbit):
r2​=22r0​=4r0​Step 6: Calculate the de-Broglie Wavelength
Plug
r2​ into the earlier formula:
λ=22πr2​​=22π​×4r0​=4πr0​