Electromagnetic waves

Содержание и основные понятия

The electromagnetic wave consists of mutually perpendicular fluctuations of the electric and magnetic fields and can be distributed in a vacuum.
GEF · Grade 9
PIF · Baseline
Interactive model
Radio waves
infrared
visible light
Ultraviolet
X-rays
01
The physical picture
What happens and what boundaries the model has.
Main message
The electromagnetic wave consists of mutually perpendicular fluctuations of the electric and magnetic fields and can be distributed in a vacuum.
All spectrum ranges are of the same nature and differ in frequency and length.
In the vacuum, the velocity of all electromagnetic waves is the same.
Radiation transports energy and impulse and interacts with the substance according to frequency.
How to reason
First, name the system and the interaction, then select the values, and only then write down the law. The formula works within the model's assumptions.
02
Laws and values
Symbols should be read as a relationship of values, not as a recipe for substitution.
c
=
λ
ν
c=\lambda\nu
c
=
λ
ν
Wave communications
E
=
h
ν
E=h\nu
E
=
h
ν
Quantum energy
Review of the situation
The 100 MHz radio wave is about 3 m long in a vacuum.
04
Links and application
In the real world
The 100 MHz radio wave is about 3 m long in a vacuum.
Model verification
Compare the prediction with observation, evaluate the units, the order of magnitude and the influence of the factors not taken into account. Disparity does not always mean an error of law: often idealization is no longer sufficient.
C
What needs to be understood
Outcome 1
Explain the physical meaning of the topic "Electromagnetic waves" through the model, not just the formula.
Outcome 2
Clear and correctly use the terms radio waves, infrared, visible light.
Outcome 3
Indicate the conditions for the applicability of the law, verify units and limit cases.
T
Terms of the topic
The definition should indicate the physical meaning, not a substitute for a domestic synonym.
Radio waves
Electromagnetic radio frequency waves used for communications, navigation and research.
infrared
Electromagnetic radiation with wave lengths greater than visible red light and less than radio range.
visible light
The area of electromagnetic radiation perceived by the human eye is approximately 380 to 780 nm.
Ultraviolet
Electromagnetic radiation with wave lengths shorter than visible purple light and longer than X-ray light.
X-rays
X-rays: Electromagnetic waves shorter than ultraviolets capable of ionizing the substance.
F
Origin and conclusion of the formulas
The fundamental law cannot be "proven" by algebras: for each record, it is stated whether it is a definition, an experimental law, or a model effect.
c
=
λ
ν
c=\lambda\nu
c
=
λ
ν
model effect
Wave connection.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
s
T
=
λ
s_T=\lambda
s
T
​
=
λ
In one period, the electromagnetic wave shifts the same phase by the same wave length.
c
=
λ
T
c=\frac{\lambda}{T}
c
=
T
λ
​
In a vacuum, the speed is equal to the distance
ν
=
1
T
⇒
c
=
λ
ν
\nu=\frac{1}{T}\Rightarrow c=\lambda\nu
ν
=
T
1
​
⇒
c
=
λ
ν
The frequency setup provides a connection between the length and frequency of the electromagnetic wave.
Conditions:
The electromagnetic wave in the vacuum is a vacuum wave length, a frequency, and a phase velocity.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
E
=
h
ν
E=h\nu
E
=
h
ν
Postulate or Model
Quantum power.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
E
∝
ν
E\propto\nu
E
∝
ν
The thermal rays and photo effects show that the energy of a separate light supply is proportional to the frequency.
h
=
6.62607015
×
10
−
34
J
s
h=6.62607015\times10^{-34}\ \mathrm{J\,s}
h
=
6.62607015
×
1
0
−
34
J
s
The proportionality factor is the constant Planck, the value of which is derived from the experiments and recorded in SI.
E
=
h
ν
E=h\nu
E
=
h
ν
The ratio is accepted as a quantum postulate for a photon; classical wave theory itself does not prove it.
Conditions:
One photon of monochromatical electromagnetic frequency radiation, ; h is a permanent Planck.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
!
Model boundaries and typical errors
Error: Forget model condition
You can't change the formula to any situation just because it's a coincidence of letters. The key condition of this topic is that all spectrum ranges are of the same nature and differ in frequency and length.
How to Check the Mind
In the vacuum, the velocity of all electromagnetic waves is the same. Then check the unit, vector direction and result behaviour at zero or very large parameter.
Σ
Conclusion on the topic
Electromagnetic waves
The electromagnetic wave consists of mutually perpendicular fluctuations of the electric and magnetic fields and can be distributed in a vacuum.
All spectrum ranges are of the same nature and differ in frequency and length.
In the vacuum, the velocity of all electromagnetic waves is the same.
Any numerical result shall be accompanied by a unit, a sign and an explanation of its physical meaning.
The content is consistent with the FRP on Physics of the OS/OSS 2025 and the subject matter of the current lines of the PNP: I. M. Peryškin and co-authors (7–9), G. J. Mäkishev and coauthors (10–11), and with the lines "Engineers of the Future" and V. A. Kasyanov. The original texts are not reproduced, the text of the textbooks is not reproduced.