Electromagentic spectrum Flashcards
What is a common way to transmit energy from one location to another?
A common way to transmit energy from one location to another is via a wave.
What is a wave?
A wave is where energy is moved from one location to another, but the particles in between have no overall movement.
Can energy be transmitted without moving any matter?
Energy can also be transmitted without moving any matter.
What are the two categories of waves?
Mechanical (require a medium), and
Electromagnetic (DO NOT require medium).
What is the amplitude?
The amplitude ( ) of a wave is the distance from the centre line (or the still position) to the top of a crest or to the bottom of a trough .
What is the amplitude measured in?
It is usually measured in metres, m and has the symbol, a.
What is wavelength?
Wavelength is like the distance between two adjacent peaks or two adjacent troughs.
Or, wavelength is the time required to complete one full cycle of the wave.
What is wavelength measured in?
It is usually measured in metres, m and has the symbol, λ (lamda).That is, how many wavelengths per second.
What is the frequency of a wave?
Frequency is the number of wave cycles passing a point per unit time.
A higher frequency means a shorter wavelength, and a lower frequency means a longer wavelength.
What are the two categories of waves?
Mechanical (require a medium), and
Electromagnetic (DO NOT require medium).
There are two basic types of wave motion:
longitudinal waves, and
transverse waves.
What is a longitudinal wave?
In a longitudinal wave the particle displacement is parallel to the direction of wave propagation.
The wave is seen as the motion of the compressed region, which moves from left to right.
What is a transverse wave?
In a transverse wave the particle displacement is perpendicular to the direction of wave propagation.
These are what you typically think of when you hear the word ‘wave’.
For example, light waves.
How do longitudinal waves move?
particles move backwards and forwards in the same direction of the wave
what is the medium in a wave?
The material through which a wave travels.
The more elastic the particles are in a mechanical wave the…..
further, the wave travels
What can the human eye see on the EMS spectrum?
The human eye can only detect only a small portion of this spectrum called visible light.
velocity/speed
Is calculated bu wavelength times frequency
Imagine you are creating a public service video warming people of the dangers of ultraviolet light. What important information would you need to get across to people? Include tips for protecting the skin from ultraviolet light.
Ultraviolet light or lamps can cause the following issues:
* Skin cancer: UV radiation is the main cause of skin cancer.
* Eye damage: UV radiation can damage the cornea and retina, and can cause cataracts.
* Suppression of the immune system: Exposure to UV radiation can decrease the body’s ability to fight off infections.
* Premature aging: UV radiation can cause premature wrinkles, age spots, and dryness of the skin.
To protect yourself from the dangers of ultraviolet light: wear sunglasses and longsleeves when outdoors; choose a good sunscreen that protects you from UV rays; stay out of the sun when possible - especially between the hours of 12 pm - 3 pm when the UV rays at their strongest.
Q
How are X rays and gamma rays used in medicine?
X-rays contain enough energy to penetrate through soft tissue but are not strong enough to penetrate through hard bone. Medical x-rays are used to generate images of tissues and structures inside the body. If x-rays traveling through the body also pass through an x-ray detector on the other side of the patient, an image will be formed that represents the “shadows” formed by the objects inside of the body.
Gamma rays possess they highest amount of energy. This means that they can penetrate down into our DNA. They can be used to kill cancers cells or to sterilise equipment by killing bacteria and other organisms that may be on them.
Describe how wave frequency changes across the electromagnetic spectrum, from radio waves to gamma rays.
Frequency is inversely proportional to the wavelength. That is, as the wavelength decrease then the frequency will increase. As we move from radio waves (long wavelength and low frequency) across to gamma rays (short wavelength and high frequency) the wavelength decrease and the frequency increases (along with the energy that the waves possess).
What is the electromagnetic spectrum (EMS)?
What are the three uses of radio waves?
AM and FM radios
police radar
GPS
ultraviolet ray
10^-8m - Emitted from the sun and can cause skin cancer
X ray
10^-10m - Used from medical imaging
infarared
10^-5m or 0.01 mm - Used for remote controls, optical fibers and monitoring temperature.
microwave
10^-2m or 1cm - used for communication and cooking food
Radio wave
1m-10^4m - used mainly for communcations
Gamma ray
10^-15m - used to treat or diagnose cancers
Visible light
10^-7m- allows us to see and used for photography
Can I identify the movement of energy and particles in transverse and longitudinal waves?
Transverse: particles move perpendicular (up and down) to the direction of the wave
Longitudinal: particles move backwards and forwards in the same direction of the wave
. Can I explain why red is always on top of a rainbow and violet is on the inside?
Red light has the longest wavelength and will bend the least.
Violet light has the shortest wavelength and will bend the most.
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Can I explain the relationship between wavelength and frequency
The shorter the wavelength, the higher the frequency the energy of the wave and the more energy it possesses.
light waves vs sound waves
Light waves are electromagnetic waves while sound waves are mechanical waves. Light waves are transverse while sound waves are longitudinal. Light waves can travel in vacuum. Sound waves require a material medium to travel, and hence, cannot travel in vacuum
The higher the frequency the higher
energy in the wave
All EM waves are
radiation
All EM waves travel at the same
speed
