Difference between revisions of "Waves and Electromagnetic Radiation"

Latest revision as of 17:52, 25 October 2026

⇱ All 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; E_photon = 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. E_photon = 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. θ_i = θ_r 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/d_o + 1/d_i relates the focal length to the object and image distances, and h_i/h_o = −d_i/d_o gives the magnification; the minus sign means a real image (positive d_i) is inverted. These two equations are new in the 2025 edition, for HS-PS4-6.

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	E_photon = hf
	Emission Spectra and Nuclear Fusion	Question 22	HS-PS4-1	E_photon = 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	θ_i = θ_r
Physics sample clusters (spring 2025)	Automotive Optics	Question 4	HS-PS4-6	h_i/h_o = −d_i/d_o

@@ Line 7: / Line 7: @@
 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]]; ''E''<sub>photon</sub> = ''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.
-<div style="display:flex;flex-wrap:wrap;gap:16px 32px;align-items:flex-start;">
+<div id="wave-speed"></div><div id="period"></div><div id="photon-energy"></div><div id="reflection"></div><div id="index-of-refraction"></div><div id="snell"></div><div id="index-ratio"></div><div id="lens-equation"></div><div id="magnification"></div>
-<div style="min-width:0;">
+[[File:Waves and Electromagnetic Radiation.png|760px|class=img-fluid|alt=Waves and Electromagnetic Radiation from the Physics Reference Tables (2025 Edition)]]
-{| class="wikitable" style="text-align:center;"
-! Equations
-|- id="wave-speed"
-| style="padding:8px 16px;" | ''v'' = ''f''λ
-|- id="period"
-| style="padding:8px 16px;" | ''T'' = <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">1</span><span style="display:block;padding:0 3px;">''f''</span></span>
-|- id="photon-energy"
-| style="padding:8px 16px;" | ''E''<sub>photon</sub> = ''hf''
-|- id="reflection"
-| style="padding:8px 16px;" | θ<sub>i</sub> = θ<sub>r</sub>
-|- id="index-of-refraction"
-| style="padding:8px 16px;" | ''n'' = <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">''c''</span><span style="display:block;padding:0 3px;">''v''</span></span>
-|- id="snell"
-| style="padding:8px 16px;" | ''n''<sub>1</sub> sin θ<sub>1</sub> = ''n''<sub>2</sub> sin θ<sub>2</sub>
-|- id="index-ratio"
-| style="padding:8px 16px;" | <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">''n''<sub>2</sub></span><span style="display:block;padding:0 3px;">''n''<sub>1</sub></span></span> = <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">''v''<sub>1</sub></span><span style="display:block;padding:0 3px;">''v''<sub>2</sub></span></span> = <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">λ<sub>1</sub></span><span style="display:block;padding:0 3px;">λ<sub>2</sub></span></span>
-|- id="lens-equation"
-| style="padding:8px 16px;" | <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">1</span><span style="display:block;padding:0 3px;">''F''</span></span> = <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">1</span><span style="display:block;padding:0 3px;">''d''<sub>o</sub></span></span> + <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">1</span><span style="display:block;padding:0 3px;">''d''<sub>i</sub></span></span>
-|- id="magnification"
-| style="padding:8px 16px;" | <span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">''h''<sub>i</sub></span><span style="display:block;padding:0 3px;">''h''<sub>o</sub></span></span> = −<span style="display:inline-block;vertical-align:middle;text-align:center;line-height:1.25;"><span style="display:block;border-bottom:1px solid currentColor;padding:0 3px;">''d''<sub>i</sub></span><span style="display:block;padding:0 3px;">''d''<sub>o</sub></span></span>
-|}
-</div>
-<div style="min-width:0;">
-{| class="wikitable"
-! Variables
-|-
-| ''c'' = speed of light in a vacuum
-|-
-| ''d''<sub>i</sub> = distance to image
-|-
-| ''d''<sub>o</sub> = distance to object
-|-
-| ''E''<sub>photon</sub> = energy of photon
-|-
-| ''F'' = focal length
-|-
-| ''f'' = frequency
-|-
-| ''h'' = Planck's constant
-|-
-| ''h''<sub>i</sub> = image height
-|-
-| ''h''<sub>o</sub> = object height
-|-
-| ''n'' = absolute index of refraction
-|-
-| ''T'' = period
-|-
-| ''v'' = velocity ''or'' speed
-|-
-| λ = wavelength
-|-
-| θ = angle
-|-
-| θ<sub>i</sub> = angle of incidence
-|-
-| θ<sub>r</sub> = angle of reflection
-|}
-</div>
-</div>
 == What the waves page shows ==
@@ Line 78: / Line 18: @@
 '''Lenses and mirrors.''' 1/''F'' = 1/''d''<sub>o</sub> + 1/''d''<sub>i</sub> relates the focal length to the object and image distances, and ''h''<sub>i</sub>/''h''<sub>o</sub> = −''d''<sub>i</sub>/''d''<sub>o</sub> gives the magnification; the minus sign means a real image (positive ''d''<sub>i</sub>) is inverted. These two equations are new in the 2025 edition, for [[HS-PS4-6]].
-== Rows ==
-Each row of the table has an anchor, so a link or an <code><nowiki>{{Rt}}</nowiki></code> chip ([[Template:Rt]]) can point at one equation or constant:
-* <code>wave-speed</code> – ''v'' = ''f''λ
-* <code>period</code> – ''T'' = 1/''f''
-* <code>photon-energy</code> – ''E''<sub>photon</sub> = ''hf''
-* <code>reflection</code> – θ<sub>i</sub> = θ<sub>r</sub>
-* <code>index-of-refraction</code> – ''n'' = ''c''/''v''
-* <code>snell</code> – ''n''<sub>1</sub> sin θ<sub>1</sub> = ''n''<sub>2</sub> sin θ<sub>2</sub>
-* <code>index-ratio</code> – ''n''<sub>2</sub>/''n''<sub>1</sub> = ''v''<sub>1</sub>/''v''<sub>2</sub> = λ<sub>1</sub>/λ<sub>2</sub>
-* <code>lens-equation</code> – 1/''F'' = 1/''d''<sub>o</sub> + 1/''d''<sub>i</sub>
-* <code>magnification</code> – ''h''<sub>i</sub>/''h''<sub>o</sub> = −''d''<sub>i</sub>/''d''<sub>o</sub>
 == Regents Exam Questions ==