Physics (2018) | JEE 2018 | Discussion Page

If the series limit frequency of the Lyman series is v_L, the the series limit frequency of the Pfund series is

$25v_{L}$

$16v_{L}$

$\frac{v_{L}}{16}$

$\frac{v_{L}}{25}$

Option D

Key idea Series limit occurs in the transition n₂= $\infty$ to n₁= 1 in Lyman series and n₂= $\infty$ to n₁=5 in pfund series. For Lyman series,

$hv_{L}=13.6$ ..........(i)

In pfund series

$hv_{p}=\frac{13.6}{5^{2}}$ ........(ii)

From Eqs. (i) and (ii), we get

$25hv_{p}=hv_{L}$

$\therefore$ $v_{p}=\frac{v_{L}}{25}$

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