TS EAMCET 5-Aug-2021 Shift 2 Question Paper

Ratio of highest to lowest wavelength of Lyman series is as follows:
For Lyman series
n1=1⇒n2=2......∞
For highest wavelength, energy should be minimum.
E=‌

hc

λ

;E∝‌

1

λ

So, when
n1=1,n2=2λ=λmax
Using the formula
‌

1

λ

‌‌=RH[‌

1

n12

−‌

1

n22

]
‌

1

λ

‌‌=RH[‌

1

(1)2

−‌

1

(2)2

]. . . (i)
λmax‌‌=‌

4

3RH

When n1=1,n2=∞,λ=λmin
‌

1

λ

‌‌=RH[‌

1

(1)2

−‌

1

(∞)2

]. . . (ii)
λmin‌‌=‌

1

RH

On comparing (i) and (ii)
‌

λmax

λmin

=‌

4×RH

3RH×1

=‌

4

3