Q.] Determine the frequency[f] of revolution of an electron in the second orbit of helium atom.
ANS:- Data :
z = 2, n= 2, nth =2nd , v = 2.18 x 106 ms-1 , find frequency(f).
Now,
n= v/ 2 pie r
n = 2.18 x 106 ms-1 / 2 x 3.14 x 0. 529 x 10-10 m
n = [ 2.18 x 106 / 2 x 3.14 x 0.529 ] s-1 .
n = [ 2.18 x 1016 / 2 x 3.14 x 0.529 ] s-1
n = 6.562 x 1015 [ f of atom in ground state of hydrogen atom ]
Hence,
n = 6.562 x 1015 x 2
n = 13.124 x 105 (Hz) .
[ is this correct method ? am i in right direction? ]























What is n in the solution? The solution is given below:

ν=cλλ=hmvSo, ν=cmvhc=velocity of lighth= Planck's constantm=mass of electronv=velocity of electron in nth orbit
Velocity of electron in 2nd orbit of He,
vn=2.18×106×Znm/sv2=2.18×106×22 m/s    =2.18×106 m/s
ν=cmvhν=3×108 ms-1×9.1×10-31 kg×2.18×106 ms-16.626×10-34 kgm2s-2.s  =8.98×1017 s-1

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