Question

Calculate the wavenumber of the first line in paschen series of hydrogen spectrum.

Answer 1

wave number = R( 1/n1^2 - 1/n2^2)
= 109677 ( 1 / 3^2 - 1/4^2)
= 109677 ( 1/9 - 1/16)
= 109677 ( 16 - 9 / 144 )
= 761.64 × 7
= 5331.48

Answer 2

Answer:

109700/cm

Explanation:

In the hydrogen spectrum we discover exclusive strains withinside the spectrum because of the version of wavelength of the photons that releases from the atom. When an electron jumps from any better orbit to 3rd

orbit to the strains which are located withinside the spectrum is referred to as the Paschen collection.

The first line of the Paschen collection is the road while an electron jumps from the 4th

to 3rd

orbit and the second one line of paschen collection is the road located while an electron jumps from 5th

orbit to 3rd orbit. Now, the wave variety of Paschen collection is given by,  

1λ=R(132−1n2)

So, placing the price for first line n=4

we have,

1λ1=R(132−142)

⇒1λ1=1.1×107(132−142)

Upon simplifying we have ,

λ1=1447×1.1×10−7

⇒λ1=1870nm

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