Question
Physics Question on Atoms
The shortest wavelength in Lyman series is 91.2nm. The longest wavelength of the series is
A
121.6nm
B
182.4nm
C
243.4nm
D
364.8nm
Answer
121.6nm
Explanation
Solution
The wavelength (λ) of lines is given by λ1=R(121−n21) For Lyman series, the shortest wavelength is for n=∞ and longest is for n=2 ∴λS1=R(121)… (i) λL1=R(11−221)=43R… (ii) Dividing E (ii) by E (i), we get λSλL=34 Given, λS=91.2nm ⇒λL=91.2×34 =121.6nm