Radius of first orbit in H -atom is ' a ₀ ' Then, de-Broglie wavelength of electron in the third orbit is

Step-by-step solution

aligned & Radius for n ^ th orbit, r _ n = a ₀ n ^2 & For third orbit, & r ₃= a ₀ 3^2 & =9 a ₀ & Also, mvr = nh 2 & mv = nh 2 r = 3 ~h 2 9 a ₀ & = h mv = h 3 ~h 2 9 a ₀=6 a ₀ aligned