<< Chapter < Page Chapter >> Page >
  • List three “rules of thumb” that apply to the different frequencies along the electromagnetic spectrum.
  • Explain why the higher the frequency, the shorter the wavelength of an electromagnetic wave.
  • Draw a simplified electromagnetic spectrum, indicating the relative positions, frequencies, and spacing of the different types of radiation bands.
  • List and explain the different methods by which electromagnetic waves are produced across the spectrum.

In this module we examine how electromagnetic waves are classified into categories such as radio, infrared, ultraviolet, and so on, so that we can understand some of their similarities as well as some of their differences. We will also find that there are many connections with previously discussed topics, such as wavelength and resonance. A brief overview of the production and utilization of electromagnetic waves is found in [link] .

Electromagnetic waves
Type of EM wave Production Applications Life sciences aspect Issues
Radio&TV Accelerating charges Communications Remote controls MRI Requires controls for band use
Microwaves Accelerating charges&thermal agitation Communications Ovens Radar Deep heating Cell phone use
Infrared Thermal agitations&electronic transitions Thermal imaging Heating Absorbed by atmosphere Greenhouse effect
Visible light Thermal agitations&electronic transitions All pervasive Photosynthesis Human vision
Ultraviolet Thermal agitations&electronic transitions Sterilization Cancer control Vitamin D production Ozone depletion Cancer causing
X-rays Inner electronic transitions and fast collisions Medical Security Medical diagnosis Cancer therapy Cancer causing
Gamma rays Nuclear decay Nuclear medicineSecurity Medical diagnosis Cancer therapy Cancer causing Radiation damage

Connections: waves

There are many types of waves, such as water waves and even earthquakes. Among the many shared attributes of waves are propagation speed, frequency, and wavelength. These are always related by the expression v W = size 12{v rSub { size 8{W} } =fλ} {} . This module concentrates on EM waves, but other modules contain examples of all of these characteristics for sound waves and submicroscopic particles.

As noted before, an electromagnetic wave has a frequency and a wavelength associated with it and travels at the speed of light, or c size 12{c} {} . The relationship among these wave characteristics can be described by v W = size 12{v rSub { size 8{W} } =fλ} {} , where v W size 12{v rSub { size 8{W} } } {} is the propagation speed of the wave, f size 12{f} {} is the frequency, and λ size 12{λ} {} is the wavelength. Here v W = c size 12{v rSub { size 8{W} } =c} {} , so that for all electromagnetic waves,

c = . size 12{c = fλ} {}

Thus, for all electromagnetic waves, the greater the frequency, the smaller the wavelength.

[link] shows how the various types of electromagnetic waves are categorized according to their wavelengths and frequencies—that is, it shows the electromagnetic spectrum. Many of the characteristics of the various types of electromagnetic waves are related to their frequencies and wavelengths, as we shall see.

An electromagnetic spectrum is shown. Different wave category regions are indicated using double sided arrows based on the values of their wavelength, energy, and frequency; the visual strip is also shown. The radio wave region is further segmented into AM radio, FM radio, and microwaves bands.
The electromagnetic spectrum, showing the major categories of electromagnetic waves. The range of frequencies and wavelengths is remarkable. The dividing line between some categories is distinct, whereas other categories overlap.

Questions & Answers

the diagram of the digestive system
Assiatu Reply
allimentary cannel
Ogenrwot
How does twins formed
William Reply
They formed in two ways first when one sperm and one egg are splited by mitosis or two sperm and two eggs join together
Oluwatobi
what is genetics
Josephine Reply
Genetics is the study of heredity
Misack
how does twins formed?
Misack
What is manual
Hassan Reply
discuss biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles
Joseph Reply
what is biology
Yousuf Reply
the study of living organisms and their interactions with one another and their environments
AI-Robot
the study of living organisms and their interactions with one another and their environment.
Wine
discuss the biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles in an essay form
Joseph Reply
what is the blood cells
Shaker Reply
list any five characteristics of the blood cells
Shaker
lack electricity and its more savely than electronic microscope because its naturally by using of light
Abdullahi Reply
advantage of electronic microscope is easily and clearly while disadvantage is dangerous because its electronic. advantage of light microscope is savely and naturally by sun while disadvantage is not easily,means its not sharp and not clear
Abdullahi
cell theory state that every organisms composed of one or more cell,cell is the basic unit of life
Abdullahi
is like gone fail us
DENG
cells is the basic structure and functions of all living things
Ramadan
What is classification
ISCONT Reply
is organisms that are similar into groups called tara
Yamosa
in what situation (s) would be the use of a scanning electron microscope be ideal and why?
Kenna Reply
A scanning electron microscope (SEM) is ideal for situations requiring high-resolution imaging of surfaces. It is commonly used in materials science, biology, and geology to examine the topography and composition of samples at a nanoscale level. SEM is particularly useful for studying fine details,
Hilary
cell is the building block of life.
Condoleezza Reply
what is cell divisoin?
Aron Reply
Diversity of living thing
ISCONT
what is cell division
Aron Reply
Cell division is the process by which a single cell divides into two or more daughter cells. It is a fundamental process in all living organisms and is essential for growth, development, and reproduction. Cell division can occur through either mitosis or meiosis.
AI-Robot
What is life?
Allison Reply
life is defined as any system capable of performing functions such as eating, metabolizing,excreting,breathing,moving,Growing,reproducing,and responding to external stimuli.
Mohamed
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Basic physics for medical imaging. OpenStax CNX. Feb 17, 2014 Download for free at http://legacy.cnx.org/content/col11630/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Basic physics for medical imaging' conversation and receive update notifications?

Ask