The Balmer line ( ) appears at in hydrogen

CHEMISTRY · Single correct · CBSE · Chemistry · Structure of Atom · Structure of Atom

Problem

The Balmer

\alpha

line (

n_i=3\rightarrow n_f=2

) appears at

656\,\text{nm}

in hydrogen. The same transition in a singly ionised, hydrogen-like atom of unknown atomic number

Z

is observed at

72.9\,\text{nm}

. The value of

Z

for this ion is (a)

Z = 9

(b)

Z = 2

(c)

Z = 3

(d)

Z = 4