Electrons and protons (attract/repel) each other. As an electron gets closer to the nucleus, the (attraction/repulsion) to the nucleus (increases/decreases). When an electron moves from energy level five to energy level two, it moves from a (higher/lower) energy state to a (higher/lower) energy state.

Electrons closest to the nucleus will have the lowest energy. Electrons further away from the nucleus will have higher energy. An atom’s electron shell can accommodate 2n2 electrons (where n is the shell level). In a more realistic model, electrons move in atomic orbitals, or subshells.

The energy levels in an atom are similar to the rungs of a ladder, but they get closer together as they get farther from the nucleus. For an electron to move from one energy level to the next higher level, it must gain the right amount of energy.

The model in the Figure below shows the first four energy levels of an atom. Electrons in energy level I (also called energy level K) have the least amount of energy. As you go farther from the nucleus, electrons at higher levels have more energy, and their energy increases by a fixed, discrete amount.

When the electron changes levels, it decreases energy and the atom emits photons. The photon is emitted with the electron moving from a higher energy level to a lower energy level. The energy of the photon is the exact energy that is lost by the electron moving to its lower energy level.

The simplest answer is that when a photon is absorbed by an electron, it is completely destroyed. All its energy is imparted to the electron, which instantly jumps to a new energy level. The photon itself ceases to be. The opposite happens when an electron emits a photon.

A photon with the appropriate energy can kick up to a higher quantized level the electron and then it will be absorbed/disappear. In this case, of a potential well, one photon can be absorbed by the system electron-in-potential-well at a time.

Gamma rays

The energy associated with a single photon is given by E = h ν , where E is the energy (SI units of J), h is Planck’s constant (h = 6.626 x 10–34 J s), and ν is the frequency of the radiation (SI units of s–1 or Hertz, Hz) (see figure below).

3×10−19J.

Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space. This proved that radio waves were a form of light!

A photon will lose energy due to absorption or inelastic scattering. Photons can be absorbed by electrons in atomic levels (which results in an increase in the energy of the latter). This process is akin to making photons vanish. Inelastic scattering will cause photons to lose (part of) their energy to other particles.

The energy of the photon depends on its frequency (how fast the electric field and magnetic field wiggle). The higher the frequency, the more energy the photon has. As the frequency of a photon goes up, the wavelength () goes down, and as the frequency goes down, the wavelength increases.

During the fall it emits a photon. From this equation, it is clear that the energy of a photon is directly proportional to its frequency and inversely proportional to its wavelength. Thus as frequency increases (with a corresponding decrease in wavelength), the photon energy increases and visa versa.

What happens to the kinetic energy of the electrons? Halving the wavelength doubles the frequency and, thus, doubles the energy of the incident photons. This doubles the energy given to each electron, nearly doubling its kinetic energy after it is free from the metal.

As a wavelength increases in size, its frequency and energy (E) decrease. From these equations you may realize that as the frequency increases, the wavelength gets shorter. As the frequency decreases, the wavelength gets longer. There are two basic types of waves: mechanical and electromagnetic.

Hence, if the wavelength is doubled, the energy of photon will be half.

The wavelength and frequency of light are closely related. The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength.

The relationship between momentum and wavelength for matter waves is given by p = h/λ, and the relationship energy and frequency is E = hf. The wavelength λ = h/p is called the de Broglie wavelength, and the relations λ = h/p and f = E/h are called the de Broglie relations.

The colour of visible light depends on its wavelength. These wavelengths range from 700 nm at the red end of the spectrum to 400 nm at the violet end. Visible light waves are the only electromagnetic waves we can see.