Consider 3rd orbit of He+ (Helium), using non-relativistic approach, the speed of electron in this orbit will be [given K = 9 × 109 constant, Z = 2 and h (Planck's Constant) = 6.6 × 10 - 34 J s] (a) 0.73 × 106 m/s (b) 3.0 × 108 m/s (c) 2.92 × 106 m/s (d) 1.46 × 106 m/s

Answer: (d). vn = (2π kZe²)/(nh) v₃ = 2π×9×10⁹×2×(1.6×10⁻¹⁹)²3×6.6×10⁻³⁴ v₃ ≈ 1.46×10⁶ m/s (same as 2.19×10⁶×2/3) So the answer is (d) 1.46×10⁶ m/s.

Consider 3rd orbit of He+ (Helium), using non-relativistic approach… | NEET 2015 (AIPMT, Cancelled Paper)

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Bohr Model: Orbits, Speed & Angular Momentum

Consider 3rd orbit of He+ (Helium), using non-relativistic approach, the speed of electron in this orbit will be [given K = 9 $\times$ 109 constant, Z = 2 and h (Planck's Constant) = 6.6 $\times$ 10 $-$ 34 J s]

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Answer: (d)

$v_n = \frac{2\pi kZe^2}{nh}$
$v_3 = \frac{2\pi\times9\times10^9\times2\times(1.6\times10^{-19})^2}{3\times6.6\times10^{-34}}$
$v_3 \approx 1.46\times10^6\text{ m/s}$ (same as $2.19\times10^6\times\frac{2}{3}$ )
So the answer is (d) $1.46\times10^6\text{ m/s}$ .

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Bohr Model: Orbits, Speed & Angular Momentum question from NEET 2015 (AIPMT, Cancelled Paper)

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