Answer:
the wavelength of radiation emitted is 
Explanation:
The energy of the Bohr's hydrogen atom can be expressed with the formula:

For n = 7:


For n = 4


The electron goes from the n = 7 to the n = 4, then :


Wavelength of the radiation emitted:

where;
hc = 1242 eV.nm


The change of energy : 4.8744 x 10⁺¹⁹ J
<h3>Further explanation</h3>
Radiation energy is absorbed by photons
The energy in one photon can be formulated as

Where
h = Planck's constant (6,626.10⁻³⁴ Js)
f = Frequency of electromagnetic waves
f = c / λ
c = speed of light
= 3.10⁸
λ = wavelength
The wavelength is 4078 A = 4.078 x 10⁺⁷ m

Answer:?Any one have the answers?
Explanation:d
To arrange the sublevels in order of increasing energy, we add the principal shell and the maximum number of electrons of the specific sublevel. s has 2 electrons, p has 6 electrons, d has 10 electrons, and f and 14 electrons. in this case, a) 3 + 10 = 13b) 2 + 2 = 4c) 4 + 2 = 6d) 3 + 6 = 9
The order hence is 2s, 4s, 3p, and 3d