The first line of the lyman series in a hydrogen spectrum has a wavelength of 1210 Å. The corresponding line of a hydrogen like atom of `Z=11` is equal to

Options

A. 4000 Å
B. 100 Å
C. 40 Å
D. 10 Å

Answer

D

Explanation

In the case of hydrogen atom,
`Z=1, (1)/(lambda)=R(3)/(4)`
For hydrogen like atom, Z = 11
`(1)/(lambda') =121 R (3)/(4)`
`rArr (lambda')/(lambda)=(3R)/(4)xx(4)/(121R xx 3)=(1)/(121)`
`or lambda' =(lambda)/(121)=(1210)/(121)=10` Å