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If a 0 is denoted as the Bohr radius of hydrogen atom, then what is the de-Broglie wavelength ( λ ) of the electron present in the second orbit of hydrogen atom ? [n : any integer]

1. π n a 2 0
2. n a 8 0 π
3. n a 4 0 π
4. 0 a n 4 π

Correct answer: n a 8 0 π

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