Question

What is the change in the orbit radius when the electron in the hydrogen atom (Bohr model) undergoes the first Paschen transition

Answer 1

$$\begin{gathered} Bohrradiusisgivenby \\ {r}_n=\frac{0.529n^2}{z} \\ Paschenseriestransitionis{n}_1=3and{n}_2=4forfirsttransitionseries. \\ {r}_n=\frac{0.529n^2}{z} \\ {r}_3=\frac{0.529\times 3^2}{1} \\ {r}_4=\frac{0.529\times 4^2}{1} \\ {r}_4-r_3=\frac{0.529\times 4^2}{1}-\frac{0.529\times 3^2}{1}=0.529\times (16-9)=3.703A^0 \end{gathered}$$