Consider third orbit of He + (helium), using non-relativistic approach, the speed of electron in this orbit…

Consider third orbit of He+ (helium), using non-relativistic approach, the speed of electron in this orbit will be given constant K=9×109, Z=2 and h (Planck's Constant)= 6.6 × 10−34 J s

  1. 2.92×106 m s-1
  2. 1.46×106 m s-1
  3. 0.73×106 m s-1
  4. 3.0×108 m s-1

Solution

Energy of electron He+
$E_n$=-13.6Z2n2 eV; Z=2, n=3
E3= -13.6 232×1.6×10-19 J
In Bohr's model energy, E=- KE
E3=-KE3
∴ 9.7×10-19=12mv2
v= 2×9.7×10-199.1×10-31
Velocity of electron in third orbit of He+ is 1.46×106 m s-1.

Asked in: NEET 2015 (Phase 1)

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