Question

Consider an electron in a hydrogen atom, revolving in its second excited state (having radius $4.65\,?$). The de-Broglie wavelength of this electron is :

• A. 12.9 ?
• B. 3.5 ?
• C. 9.7 ?
• D. 6.6 ?

Answer 1

Answer: (C)

9.7 ?

Answer 2

$2\pi r_n \, = \, n \lambda_n$
$\lambda_3 \, = \, \frac{2 \pi (4.65 \times 10^{-10})}{3}$
$\lambda_3 = 9.7\, ?$