Question

If the radius of first Bohr's orbit is x ,then de-Broglie wavelength of electron in 3rd orbit is nearly

• A. $2 \pi x$
• B. 6 $\pi$ x
• C. 9 x
• D. x /3

Answer 1

Answer: (B)

6 $\pi$ x

Answer 2

$m \nu r = \frac{nh}{2 \pi } \left( r = \frac{r_0 n^2}{Z} \right) r_0 = x$ $2 \pi r = n \lambda \, \Rightarrow \, \lambda = \frac{2 \pi r}{n} = 6 \pi \, x$