Quantum Physics Unit Review

Comprehensive vocabulary flashcards covering the nature of light, nuclear physics, radioactive decay, nuclear reactions, the quantum mechanical model, and modern quantum technologies.

Electromagnetic Waves in Vacuum

All electromagnetic waves travel at the same speed ($3.0 imes 10^8 ext{ m/s}$) when moving through a vacuum.

Wavelength and Frequency Relationship

As wavelength increases, frequency decreases, demonstrating an inverse relationship.

Gamma Rays

The type of electromagnetic wave that possesses the highest energy and the shortest wavelengths.

Visible Light Spectrum

A narrow band in the electromagnetic spectrum located between infrared and ultraviolet radiation.

Wave-Particle Duality

The concept that light behaves as both a wave (evidenced by interference patterns) and a particle (evidenced by the photoelectric effect).

Thomas Young's Double-Slit Experiment

An important experiment that proved the wave nature of light by demonstrating interference patterns.

Quanta

Discrete packets of energy that make up light, a concept first proposed by Max Planck.

Photon Energy Equation

$E = hf$, where $E$ is energy, $h$ is Planck's constant, and $f$ is frequency.

Photoelectric Effect

The phenomenon where light acts as a particle to eject electrons from a metal surface; Albert Einstein won the Nobel Prize for explaining this.

Work Function

The minimum energy required to eject an electron from a metal surface; low-frequency light fails to eject electrons because individual photons lack the energy to overcome this threshold.

Planck's Constant ($h$)

A fundamental physical constant with the value of $6.626 imes 10^{-34} ext{ J} ext{·} ext{s}$.

Atomic Number ($Z$)

The number of protons in the nucleus of an atom, identifying the element.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Nucleons

The collective name for the protons and neutrons found within the nucleus.

Binding Energy

The energy equivalent of the mass defect that holds a nucleus together, calculated using $E = mc^2$.

Mass Defect

The difference between the total mass of individual nucleons and the actual (lighter) mass of the assembled nucleus.

Strong Nuclear Force

The force that holds protons together in the nucleus despite their electromagnetic repulsion; it has a very short range.

Alpha Particle

A helium nucleus consisting of $2$ protons and $2$ neutrons with a charge of $+2$; it is the least penetrating type of radiation.

Beta Particle

A high-speed electron emitted from the nucleus during radioactive decay.

Gamma Rays (Radiation)

High-energy electromagnetic radiation emitted during decay that has no mass or charge and requires thick lead or concrete to stop.

Radioactive Decay

A random and spontaneous process in which an unstable nucleus emits particles or energy to become more stable.

Half-Life

The constant amount of time required for half of a radioactive sample to decay, regardless of external temperature or pressure.

Nuclear Fusion

The process of joining two small nuclei to form a larger one, which releases energy and powers stars like the Sun.

Nuclear Fission

The process of splitting a heavy nucleus (like $^{235} ext{U}$) into two smaller nuclei, releasing energy and neutrons.

Critical Chain Reaction

A state in a nuclear reactor where each fission event produces exactly one neutron that triggers exactly one more fission.

Iron ($^{56} ext{Fe}$)

The element at the peak of the binding energy per nucleon curve, representing the most stable nucleus.

Control Rods

Rods made of neutron-absorbing material pushed into a reactor to slow down or stop the nuclear chain reaction.

Moderator

A substance (such as water) used in a nuclear reactor to slow down fast neutrons so they can effectively trigger fission in $^{235} ext{U}$.

Technetium-99m

A widely used medical radioisotope characterized by an ideal half-life ($6 ext{ hours}$) and gamma emission for imaging.

PET Scans

Diagnostic tools that use radioisotopes to show the function and metabolic activity of tissues, not justleur structural appearance.

Heisenberg Uncertainty Principle

The principle stating it is impossible to simultaneously know both the exact position and the exact momentum of an electron.

Atomic Orbital

A region of space where there is a high probability of finding an electron, as defined by the quantum mechanical model.

Bohr Model

An early atomic model where electrons follow fixed circular orbits; its main limitation is that it only accurately predicted the spectra for hydrogen.

Qubit

The basic unit of information in quantum computing that can represent $0$, $1$, or a superposition of both.

Quantum Entanglement

A phenomenon where two qubits are linked so that measuring one instantly determines the state of the other, regardless of distance.

Superposition

The quantum property that allows a particle to exist in multiple states at the same time.

Decoherence

The loss of a quantum state caused by environmental interference, representing a major engineering challenge for quantum computers.

LASER

An acronym for Light Amplification by Stimulated Emission of Radiation; it produces coherent light of a single precise wavelength.

Quantum Key Distribution (QKD)

A form of quantum cryptography where security is guaranteed by the laws of physics, making any eavesdropping detectable.

Photovoltaic Cell (Solar Cell)

A device that uses the photoelectric effect to convert photons into electrical current.