Calculate the number of waves by a Bohr electron in one complete revolution in its third orbit.

Explanation

We know that
Number of waves `=("Circumference of electron orbit")/("Wavelength") = (2 pi r)/(lambda)`
But ` " " lambda =( h) /( m upsilon)`
`:. " "` Number of waves ` = 2 pi r xx ( m upsilon)/(h) = ( 2 pi)/(h) ( m upsilon r) `
Thus angular momentum for Bohr's third orbit is given as :
` m upsilon r =(n h)/( 2 pi) = ( 3h)/( 2 pi )`
Substituting the value of ` m upsilon` r in expression (i),
Thus, `" "` number of waves `=( 2 pi)/( h) xx (3h)/(2 pi)=3`
Thus , the number of waves in Bohr's third orbit =3.