ans given is option @Shwetanshu_2018

# Doubt from atomic structure

Bhaiya c

Here , we know that for H atom visible region is balmer series , when instead of H , He is there for transition , then energy of transition is increased as it is proportion to z² and hence lamba of transition (for balmer series) decreases and no more lies in visible region and hence , for lower energy (i.e higher wavelength ) higher series transitions is required

We know that for H , balmer series lie in visible region , i.e E= 1/4 Eo

Now for He for E=1/4 Eo , n=4 as Z=2 therefore it must be brackett series

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