TS EAMCET 6-Aug-2021 Shift 2 Question Paper

(*) According to Bohr, the wavelength emitted when an electron jumps from n1 th to n2 th orbit is given as
‌

1

λ

=R(‌

1

n12

−‌

1

n22

)
For first line of Lyman series, n1=1 and n2=2
‌

1

λ1

=R(‌

1

12

−‌

1

22

)
∴‌‌‌

1

λ1

=R(1−‌

1

22

)=‌

3R

4

For the first line of Balmer series, n1=2 and n2=3
‌

1

λ2

=R(‌

1

22

−‌

1

32

). . . (i)
∴‌‌‌

1

λ2

=R(‌

1

4

−‌

1

9

)=‌

5R

36

. . . (ii)
∴ Dividing Eq. (ii) by Eq (i), we get
‌‌

λ1

λ2

‌‌=‌

5R

36

×‌

4

3R

⇒‌‌

5

27

‌‌=9α
⇒‌α‌‌=‌

5

27×9

=0.021