Hydrogen $(H)$, deuterium $(D)$, singly ionized helium $(H{e^ + })$ and doubly ionized lithium $(Li)$ all have one electron around the nucleus. Consider $n =2$ to $n = 1 $ transition. The wavelengths of emitted radiations are ${\lambda _1},\;{\lambda _2},\;{\lambda _3}$ and ${\lambda _4}$ respectively. Then approximately

  • A

    ${\lambda _1} = {\lambda _2} = 4{\lambda _3} = 9{\lambda _4}$

  • B

    $4{\lambda _1} = 2{\lambda _2} = 2{\lambda _3} = {\lambda _4}$

  • C

    ${\lambda _1} = 2{\lambda _2} = 2\sqrt 2 {\lambda _3} = 3\sqrt 2 {\lambda _4}$

  • D

    ${\lambda _1} = {\lambda _2} = 2{\lambda _3} = 3\sqrt 2 {\lambda _4}$

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