Q47 / 99 · NTA Abhyas (JEE Main) 2020 · Chemistry · Structure of Atom

Calculate the number of waves made by a Bohr electron in one complete revolution in nth orbit of He+ ion, if ratio of de-Broglie wavelength associated with electron moving in nth orbit and 2nd orbit is 2.0 :-

Correct answer: 4

Solution

nλ=2πr
nλ=2×π×0.529×n2Z
λn=2π×0.529×nZ ------ (i)
λ2=2π×0.529×2Z ------ (ii)
Eq (i) ÷ (ii)
λnλ2=2=n2
n=4

Hence, the correct answer is 4.

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