Introduction to Light, Spectroscopy, and the Photoelectric Effect

Flashcards covering key vocabulary terms from the lecture on light, wave-particle duality, the electromagnetic radiation spectrum, spectroscopy applications, Beer's law, and the photoelectric effect.

Wavelength

The distance between two consecutive peaks of a wave, requiring units of meters for calculations involving the speed of light.

Frequency

The number of times a wave peak or wavelength passes a specific point per second, measured in units of per second ($s^{-1}$) or hertz ($Hz$).

Speed of Light ($c$)

A physical constant connecting frequency and wavelength, calculated as $3 \times 10^8\,m/s$ for quizzes and exams.

Planck's Constant ($h$)

A fundamental physical constant with a value of $6.6 \times 10^{-34}\,J\,s$, used to calculate energy from frequency or wavelength.

Electromagnetic Radiation Spectrum

The total range of light arranged from longest to shortest wavelength (and lowest to highest energy): radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Visible Spectrum

The narrow region of electromagnetic radiation visible to human eyes, ranging from red light (longer wavelength, lower energy) to violet light (shorter wavelength, higher energy).

Nuclear Magnetic Resonance Spectroscopy

A spectroscopic technique that utilizes low-energy radio waves to excite the spin of atomic nuclei.

Infrared (IR) Spectroscopy

A technique using infrared radiation to induce and measure vibrations in molecular bonds, such as carbon-oxygen double bonds or hydroxyl groups.

Microwave Radiation

A region of the electromagnetic spectrum that probes matter by causing molecules to rotate, which generates heat in substances like food.

Ultraviolet-Visible (UV-Vis) Spectroscopy

A technique using visible light to excite valence electrons to higher energy levels, and ultraviolet light to excite valence electrons higher or completely eject them from an atom.

X-ray Radiation

High-energy electromagnetic radiation capable of exciting inner shell or core electrons within an atom.

Gamma Radiation

The highest energy region of the electromagnetic radiation spectrum, possessing enough energy to decay or split an atomic nucleus.

Beer-Lambert Law

A law utilizing ultraviolet and visible light to determine solution concentration based on light absorption, where higher concentration results in higher absorbance.

Molar Absorptivity

A sample-specific constant in Beer's Law with units of inverse molarity inverse centimeters ($M^{-1}\,cm^{-1}$).

Photoelectric Effect

The phenomenon where light shining on a metal surface ejects electrons only if individual photons meet or exceed the metal's specific threshold energy or work function.

Photon

A discrete packet or particle of light energy defined in quantum mechanics, illustrating wave-particle duality.

Work Function

The minimum threshold energy required to overcome the binding forces holding an electron to a specific metal surface.

Light Intensity (Quantum Model)

The total quantity or count of photons delivered per unit time; increasing intensity increases ejected electrons only if each individual photon possesses energy above the work function.