Q 12-12-084JEE MainJEE Main 2022 (25 Jun, Shift 1)Easy
The ratio of the speed of the electron in the 3rd orbit of $\text{He}^+$ to the speed of the electron in the 3rd orbit of hydrogen atom will be:
Answer: (D) $2 : 1$
In Bohr's model $v\propto\dfrac Zn$. For the same $n$, $\dfrac{v_{\text{He}^+}}{v_{\text H}} = \dfrac21$.
Solution by Sreeraj P, M.Sc Physics