Question

The circumference of the second orbit of an atom or ion having a single electron is $4\times 10^{- 9} \, m$ . The de Broglie wavelength of an electron revolving in this orbit should be

• A. $2\times 10^{- 9}m$
• B. $4\times 10^{- 9}m$
• C. $8\times 10^{- 9}m$
• D. $1\times 10^{- 9}m$

Answer 1

Answer: (A)

$2\pi r=n\lambda $
$\therefore \lambda =\frac{2 \pi r}{n}=\frac{4 \times \text{10}^{- 9}}{2}=2\times \text{10}^{- 9}\text{ m}$