9TH GRADE · ELECTROMAGNETIC WAVES
Electromagnetic waves and their ranges
Radio waves, IR, visible light, UV and X-rays.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Electromagnetic wave
A propagating, interconnected change in electric and magnetic fields that does not require a material medium.
Electromagnetic waves arise from the accelerated movement of charges and propagate in a vacuum at the speed of light.
Electromagnetic wave bands
Radio, microwaves, infrared, visible, ultraviolet and x-ray radiation differ in frequency.
The same nature is combined with different interactions with matter, so the ranges have different applications.
Electromagnetic Radiation Safety
The risk depends on the frequency, intensity, time of exposure and the ability of the radiation to ionize the substance.
Skin and eyes are protected from ultraviolet radiation, and work with x-rays is limited by time, distance and screens.
Physical quantities
Emission frequency
The number of oscillations of the electromagnetic field per second.
Unit: hertz ·
Lesson formulas
Electromagnetic wave speed
In a vacuum, the product of the electromagnetic wavelength and frequency is equal to the speed of light.
Related formulas
The same formulas in the reference, with symbols and units.