Answer:
The expression for the wavelength of radiation is,
λ
1
=R(
n
1
2
1
−
n
2
2
1
)
Substitute values in the above expression,
λ
1
=109677×(
2
2
1
−
4
2
1
)=109677×(
4
1
−
16
1
)=109677×(
64
12
)
λ=4.86×10
−5
cm=486×10
−9
m=486nm.
The line belongs to bluish green colour.
