Unit 7: Quantum, Atomic, and Nuclear Physics

Light being emitted as individual packets of energy called quanta.

A quantum of electromagnetic energy is known as a photon.

Light behaves like a stream of photons, illustrated by the photoelectric effect.

The released electrons are known as photoelectrons.

• The significant time delay between the moment of illumination and the ejection of photoelectrons.

• Increasing the intensity of the light could cause the electrons to leave the metal surface with greater kinetic energy.

• Photoelectrons would be emitted regardless of the frequency of the incident energy, as long as the intensity was high enough.

Minimum frequency required to produce photoelectrons from a metal.

Energy required to impart to an electron on the metal surface.

The probability that a particle will be measured to be at a particular position when the position is measured. That probability is related to a new physical parameter called the wave function.

Force binding neutrons and protons in the nucleus.

Energy required to disassemble a nucleus into its constituent nucleons.

Process of combining small nuclei at high temperatures.

Process of splitting a nucleus or emitting particles.

Emission of an alpha particle from a nucleus.

Decay processes involving the transformation of neutrons and protons.

Process where a nucleus relaxes and sheds energy in the form of a gamma ray.

Energy involved in nuclear reactions, determining if reactions are exothermic or endothermic.

The light from a glowing gas, passed through a prism to disperse the beam into its component wavelengths, produces patterns of sharp lines called atomic spectra.

Photon’s wavelength:

• λ = wavelength

• c = speed of light

• f = frequency

• h = Planck’s constant (6.626 × 10 -34 joule·s)

De-Broglie wavelength explains matter's wave-like behavior in quantum mechanics.

The equation is λ = h/p, where λ is De-Broglie wavelength, h is Planck's constant, and p is particle momentum.As momentum increases, the wavelength decreases.

This is important for understanding particle behavior at the quantum level.

Electromagnetic radiation propagates like a wave but exchanges energy like a particle. This is known as wave-particle duality.

The results of physical experiments will be the same in any-nonaccelerating reference frames.The speed of light is constant.

Demonstrated by synchronized atomic clocks.

To be consistent with time dilation, there must also be disagreement about distances. This is known as length contraction.

The nuclei that contain the same number of neutrons are called isotopes.

The total number of nucleons (Z+N), is called the mass number, and is denoted by A

The number of protons in a given nucleus is called the atom’s atomic number denoted by Z.

The strong nuclear force is a fundamental force which binds neutrons and protons together to form nuclei.