The angular momentum of an electron in a Bohr's orbit of hydrogen atom is 4.218×10−34kgm2s−1. Calculate the wavelength of the spectral line emitted, when electrons falls from this level to the next lower level.
A
1.876×10−4 cm
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
1.876×10−4 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
1.786×10−4 cm
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
1.786×10−4 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is A1.876×10−4 cm Angular momentum of an electron in a Bohr's orbit of H-atom. mvr=nh2π 4.218×10−34=n×6.626×10−342×227 ⇒n=4.218×10−34×2×226.626×10−34×7=4 Now, −ν=1λ=109678(1n21−1n22)cm−1 The spectral lines when electron falls from 4th level to 3rd level, 1λ=109678(132−142)cm−1 ⇒1λ=109678(16−99×16)cm−1 ⇒1λ=109678(79×16)cm−1 λ=9×16109678×7=1.876×10−4cm