#electron transitions

Infrared, Visible Light and Applications

Which electromagnetic waves are emitted by electrons transitioning between energy levels in atoms?

**IR effectiveness in remote sensing** because IR scattered less than visible by atmosphere, can detect heat signatures, used in satellite imaging for vegetation, moisture, military night vision, illustrating application based on thermal emission and low scattering. The document states that visible light is emitted when electrons in atoms move from one energy level to a lower energy level. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Visible light, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Infrared, Visible Light and Applications

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Shapes of Orbitals - s p d f and Nodes and Radial Probability

The number of spectral lines produced when an electron falls from n = 9 to n = 6 in a hydrogen atom is:

Number of lines = (9-6)(9-6+1)/2 = 6.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability

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Atomic Models - Thomson Rutherford and Bohr Model

The number of spectral lines produced when an electron falls from n = 8 to n = 5 in a hydrogen atom is:

Number of lines = (8-5)(8-5+1)/2 = 6.

Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Atomic Models - Thomson Rutherford and Bohr Model

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UV-VIS spectroscopy

Fluorescence emission occurs when electrons drop from:

Jablonski diagram organizes electronic states by multiplicity and energy. Upon photon absorption electron jumps from ground singlet S0 to excited singlet S1 or higher S2, then undergoes rapid internal conversion and vibrational relaxation to lowest vibrational level of S1 within picoseconds conserving spin. Fluorescence represents radiative transition from S1 lowest vibrational level to various vibrational levels of S0, emitting photon with longer wavelength and nanosecond lifetime. This distinguishes fluorescence S1→S0 from phosphorescence T1→S0 which is spin-forbidden slower, and from nonradiative S2→S1 internal conversion steps that do not emit light.

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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