The electron in the hydrogen atom undergoes transition from higher orbits to orbit of radius 211.6 pm. This transition is associated with :

$\mathrm{r}\left(\text{radius of lower orbit}\right)=0.529\times {\mathrm{n}}^2{\mathrm{A}}^{\circ }$

$2.116{\mathrm{A}}^{\circ }=0.529\times {\mathrm{n}}^2\cdot {\mathrm{A}}^{\circ }$

${\mathrm{n}}^2=4$

$\mathrm{n}=2$

Hence, the transition is from a higher orbit to the second orbit, corresponding to Balmer series.