Question

0.6
Light of wavelength 12818 Å is emitted when the electron of a hydrogen atom drops from 5th
to 3rd quantum level. Find the wave length of the photon when falls from 3rd to ground level.​

Answer 1

Answer:

The wave length of the photon when falls from 3rd to ground level is 1297822500000000 Å

Explanation:

The wavelength ,λ= 12818 Å

We know that the expression for change in energy emission is,

ΔE= hc/λ .....(1)  [ where h= plank's constant, c= speed of light, λ = the wavelength]

Now according to rydberg formula

1/λ=R(1/n^2f−1/n^2i)

ΔE= -R(1/n^2f−1/n^2i)...(2)

therefore, from i and 2 we get,

R/hc= - (1/n^2f−1/n^2i)/λ

        =  -(1/3^2−1/5^2i)/12818  [ where nf = 3 and ni = 5]

Now from 3rd to ground level,

1/λ=-R/hc (1/n^2f−1/n^2i)

putting the value,

1/λ= - (-(1/3^2−1/5^2i)/12818) (1/2^2f−1/3^2i)

 λ     = 1297822500000000 A

Answer 2

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