Summary on Electromagnetic Radiation and Atomic Spectra

Electromagnetic radiation is defined by its wavelength (λ), frequency (ν), and speed (c = 3.0 × 10⁸ m/s), which are related by the equation: c=λν
This radiation can also be described as a stream of “particles” called photons, each with energy ,where is Planck’s constant ( J·s).
When light strikes a metal surface, it can cause the emission of electrons. The analysis of the kinetic energy and quantity of these emitted electrons led Einstein to propose that electromagnetic radiation can be thought of as a stream of photons.
The photoelectric effect refers to the emission of electrons from a metal surface when exposed to electromagnetic radiation with sufficient energy. The resulting current increases with the intensity of the radiation.
According to Bohr’s theory, an electron in a hydrogen atom exists in one of a discrete set of energy levels. When an electron transitions from a higher to a lower energy level, it releases a specific amount of energy as a photon of light with a characteristic frequency.
Bohr’s theory successfully explains the observed atomic spectrum of the hydrogen atom. The emission spectrum is the range of electromagnetic radiation emitted by atoms (or other species) as a result of electron transitions from higher to lower energy states.

Electromagnetic Radiation

Electromagnetic radiation consists of waves of electric and magnetic fields propagating through space.
It includes a wide range of frequencies, from radio waves with low frequencies to gamma rays with very high frequencies

The electromagnetic spectrum categorizes electromagnetic radiation based on its wavelength or frequency.
It includes radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

Quantum theory describes the behavior of particles at the atomic and subatomic scales.
A photon is the quantum (or particle) of light, carrying energy proportional to its frequency.
Photons exhibit both wave-like and particle-like properties, known as wave-particle duality.

The photoelectric effect is the emission of electrons from a material when it is exposed to light (or electromagnetic radiation) of sufficient frequency.
It provided experimental evidence supporting the particle nature of light (photons) and led to the development of quantum theory.

Bohr’s model of the hydrogen atom proposed that electrons orbit the nucleus in quantized orbits with discrete energy levels.
Electrons emit or absorb energy in discrete packets (quanta) when transitioning between these orbits.

Bohr’s model was successful in explaining the discrete line spectra of hydrogen but failed to describe atoms with more than one electron.