Waves and Electromagnetic Radiation · Physics Reference Tables (2025 Edition)
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The Waves and Electromagnetic Radiation page of the Reference Tables for Physical Science: Physics (2025 Edition) is the waves and optics equation sheet: nine equations with the meaning of their variables. Wave speed, period, index of refraction and Snell's law support HS-PS4-1; Ephoton = hf supports HS-PS4-3 and HS-PS4-4 (and the physics side of HS-ESS1-2); the law of reflection, the lens equation and magnification support HS-PS4-6. Every equation has its own row anchor.
What the waves page shows
Waves. v = fλ relates the speed, frequency and wavelength of any wave; for light and other electromagnetic waves in a vacuum v is c from the List of Physical Constants, and for sound in air the constants list gives 331 m/s. T = 1/f converts between period and frequency.
Photons. Ephoton = hf gives the energy of a photon from its frequency, with Planck's constant from the constants list; the electronvolt entry converts the answer to eV. There is no E = hc/λ on the tables, so a wavelength has to go through v = fλ first. This is the only modern-physics equation on the 2025 tables: the 2006 edition's E = mc2, the energy-level diagrams and the standard-model tables are gone.
Reflection and refraction. θi = θr is the law of reflection. n = c/v defines the absolute index of refraction, n1 sin θ1 = n2 sin θ2 is Snell's law, and the ratio equation says that when light enters a medium of higher index its speed and wavelength drop in the same proportion while its frequency stays the same. The 2006 edition's table of indices of refraction is not in the 2025 edition, so a question gives the indices it needs.
Lenses and mirrors. 1/F = 1/do + 1/di relates the focal length to the object and image distances, and hi/ho = −di/do gives the magnification; the minus sign means a real image (positive di) is inverted. These two equations are new in the 2025 edition, for HS-PS4-6.
Rows
A link or an {{Rt}} chip (Template:Rt) can point at one equation or constant with these anchors; each one lands on the table above:
wave-speed– v = fλperiod– T = 1/fphoton-energy– Ephoton = hfreflection– θi = θrindex-of-refraction– n = c/vsnell– n1 sin θ1 = n2 sin θ2index-ratio– n2/n1 = v1/v2 = λ1/λ2lens-equation– 1/F = 1/do + 1/dimagnification– hi/ho = −di/do
Regents Exam Questions
Released Regents questions that cannot be answered without this table, listed by exam. Each link opens the question with its answer key; the standard is the one the question assesses.
| Exam | Cluster | Question | Standard | Row |
|---|---|---|---|---|
| June 2026 Physics Regents | Kidney Stone Detection and Removal | Question 7 | HS-PS4-1 | v = fλ |
| Kidney Stone Detection and Removal | Question 10 | HS-PS4-1 | Ephoton = hf | |
| Emission Spectra and Nuclear Fusion | Question 22 | HS-PS4-1 | Ephoton = hf; v = fλ | |
| The Cell Phone | Question 26 | HS-PS4-1 | n = c/v | |
| Flashlight Physics | Question 31 | HS-PS4-1 | v = fλ | |
| Voice Recognition Software | Question 44 | HS-PS4-1 | T = 1/f | |
| Physics sample clusters (spring 2025) | Automotive Optics | Question 2 | HS-PS4-6 | θi = θr |
| Automotive Optics | Question 4 | HS-PS4-6 | hi/ho = −di/do |