1. Home
  2. Maths test
  3. Maths test
  4. Electromagnetic radiation

0.6 Electromagnetic radiation  (Page 2/5)

<< Chapter < Page
  Maths test     Page 2 / 5
Chapter >> Page >

Electromagnetic radiation allows us to observe the world around us. It is this radiation which reflects off of the objects around you and into your eye. The radiation your eye is sensitive to is only a small fraction of the total radiation emitted in the physical universe. All of the different fractions taped together make up the electromagnetic spectrum.

Dispersion

When white light is split into its component colours by a prism, you are looking at a portion of the electromagnetic spectrum.

The wavelength of a particular electromagnetic radiation will depend on how it was created.

Wave nature of em radiation

  1. List one source of electromagnetic waves. Hint: consider the spectrum diagram and look at the names we give to different wavelengths.
  2. Explain how an EM wave propagates, with the aid of a diagram.
  3. What is the speed of light? What symbol is used to refer to the speed of light? Does the speed of light change?
  4. Do EM waves need a medium to travel through?

The radiation can take on any wavelength, which means that the spectrum is continuous. Physicists broke down this continuous band into sections. Each section is defined by how the radiation is created, not the wavelength of the radiation. But each category is continuous within the min and max wavelength of that category, meaning there are no wavelengths excluded within some range.

The spectrum is in order of wavelength, with the shortest wavelength at one end and the longest wavelength at the other. The spectrum is then broken down into categories as detailed in [link] .

Electromagnetic spectrum
Category Range of Wavelengths (nm) Range of Frequencies (Hz)
gamma rays < 1 > 3 × 10 19
X-rays 1-10 3 × 10 17 - 3 × 10 19
ultraviolet light 10-400 7 , 5 × 10 14 - 3 × 10 17
visible light 400-700 4 , 3 × 10 14 - 7 , 5 × 10 14
infrared 700- 10 5 3 × 10 12 - 4 , 3 × 10 19
microwave 10 5 - 10 8 3 × 10 9 - 3 × 10 12
radio waves > 10 8 < 3 × 10 9

Since an electromagnetic wave is still a wave, the following equation that you learnt in Grade 10 still applies:

c = f · λ

Calculate the frequency of red light with a wavelength of 4 , 2 × 10 - 7  m

  1. We use the formula: c = f λ to calculate frequency. The speed of light is a constant 3 × 10 8 m/s.

    c = f λ 3 × 10 8 = f × 4 , 2 × 10 - 7 f = 7 , 14 × 10 14 Hz

Ultraviolet radiation has a wavelength of 200 nm . What is the frequency of the radiation?

  1. Recall that all radiation travels at the speed of light ( c ) in vacuum. Since the question does not specify through what type of material the Ultraviolet radiationis traveling, one can assume that it is traveling through a vacuum. We can identify two properties of the radiation - w a v e l e n g t h ( 200 nm ) and speed ( c ).

  2. c = f λ 3 × 10 8 = f × 200 × 10 - 9 f = 1 . 5 × 10 15 Hz

Examples of some uses of electromagnetic waves are shown in [link] .

Uses of EM waves
Category Uses
gamma rays used to kill the bacteria in marshmallows and to sterilise medical equipment
X-rays used to image bone structures
ultraviolet light bees can see into the ultraviolet because flowers stand out more clearly at this frequency
visible light used by humans to observe the world
infrared night vision, heat sensors, laser metal cutting
microwave microwave ovens, radar
radio waves radio, television broadcasts

Questions & Answers

What is inflation
Bright Reply
a general and ongoing rise in the level of prices in an economy
AI-Robot
What are the factors that affect demand for a commodity
Florence Reply
price
Kenu
differentiate between demand and supply giving examples
Lambiv Reply
differentiated between demand and supply using examples
Lambiv
what is labour ?
Lambiv
how will I do?
Venny Reply
how is the graph works?I don't fully understand
Rezat Reply
information
Eliyee
devaluation
Eliyee
t
WARKISA
hi guys good evening to all
Lambiv
multiple choice question
Aster Reply
appreciation
Eliyee
explain perfect market
Lindiwe Reply
In economics, a perfect market refers to a theoretical construct where all participants have perfect information, goods are homogenous, there are no barriers to entry or exit, and prices are determined solely by supply and demand. It's an idealized model used for analysis,
Ezea
What is ceteris paribus?
Shukri Reply
other things being equal
AI-Robot
When MP₁ becomes negative, TP start to decline. Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of lab
Kelo
Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of labour (APL) and marginal product of labour (MPL)
Kelo
yes,thank you
Shukri
Can I ask you other question?
Shukri
what is monopoly mean?
Habtamu Reply
What is different between quantity demand and demand?
Shukri Reply
Quantity demanded refers to the specific amount of a good or service that consumers are willing and able to purchase at a give price and within a specific time period. Demand, on the other hand, is a broader concept that encompasses the entire relationship between price and quantity demanded
Ezea
ok
Shukri
how do you save a country economic situation when it's falling apart
Lilia Reply
what is the difference between economic growth and development
Fiker Reply
Economic growth as an increase in the production and consumption of goods and services within an economy.but Economic development as a broader concept that encompasses not only economic growth but also social & human well being.
Shukri
production function means
Jabir
What do you think is more important to focus on when considering inequality ?
Abdisa Reply
any question about economics?
Awais Reply
sir...I just want to ask one question... Define the term contract curve? if you are free please help me to find this answer 🙏
Asui
it is a curve that we get after connecting the pareto optimal combinations of two consumers after their mutually beneficial trade offs
Awais
thank you so much 👍 sir
Asui
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities, where neither p
Cornelius
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities,
Cornelius
Suppose a consumer consuming two commodities X and Y has The following utility function u=X0.4 Y0.6. If the price of the X and Y are 2 and 3 respectively and income Constraint is birr 50. A,Calculate quantities of x and y which maximize utility. B,Calculate value of Lagrange multiplier. C,Calculate quantities of X and Y consumed with a given price. D,alculate optimum level of output .
Feyisa Reply
Answer
Feyisa
c
Jabir
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
<< Chapter < Page Page > Chapter >>

Read also:

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Maths test. OpenStax CNX. Feb 09, 2011 Download for free at http://cnx.org/content/col11236/1.2
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Maths test' conversation and receive update notifications?

Ask