If the radius of first Bohr orbit is unit, then de-Broglie wavelength of electron in the third orbit — Atomic Structure Chemistry Question

💡 Solution & Explanation

The radius of the third orbit is $r_3 = r_1 \times 3^2 = 9x$. By Bohr's condition, $2\pi r_3 = n\lambda \implies 2\pi(9x) = 3\lambda \implies 18\pi x = 3\lambda \implies \lambda = 6\pi x$. Therefore, correct answer is B.