science EM test Flashcards
1
Q
Electromagnetic Radiation
A
is energy that travels in the form of electromagnetic waves. the movement of energy through space.
2
Q
Mechanical waves vs. Non Mechanical waves
A
- Mechanical waves need a material to move through to exist
- This is why we can’t hear anything in space, there is no air for sound to move through
- Non Mechanical waves do not need a material to move through
- This is why radio waves and microwaves can pass through the Earth’s atmosphere and travel in space.
3
Q
Wavelength
A
is the distance it takes a wave to complete one up and down motion/vibration
4
Q
Opaque and transparent relationship
A
-opaque objects absorb the colors and reflect what is being seen.
- transparent objects absorb certain wavelengths of light and transmit other wavelengths: the wavelengths of light absorbed is determined by the object’s pigments.
5
Q
Absorption
A
- when an object absorbs light, it is absorbing energy, which causes the total internal energy of the material to increase.
6
Q
Angle of incidence
A
- The angle that the light is hitting the object
- The angle of incidence is measured from the “normal”
7
Q
Angle of reflection
A
- The angle where light is bouncing away from the object
8
Q
Angle of refraction
A
- The angle that light moves when it enters a new medium
9
Q
Diffuse reflection
A
- Occurs when light bounces off a surface that is NOT flat, causing light waves to reflect at various angles.
- All of the incident rays come in parallel to each other.
- However, they do not all hit the object at the same angle.
- The reflected rays are at different angles to each other.
- Results in a blurry reflected image.
10
Q
Specular reflection
A
- Occurs when light bounces off a flat object.
- All of the incident rays come in parallel to each other.
- Since all of the light rays have the same incident angle, all of the reflected rays have the same reflected angle.
- Results in a clear reflected image.
11
Q
Normal
A
an imaginary line perpendicular
to the surface of the material.
12
Q
Reflection
A
- Waves bounce back off the matter
- White reflects all colors, black absorbs all colors
13
Q
Refraction
A
- waves pass through the matter at a different angle due to the wave’s change in speed.
14
Q
EMS
A
- Radio waves have the lowest frequency and energy, longest wavelength. Televisions and radio signals are transmitted through radio waves
- Microwaves have higher frequencies and shorter wavelengths than radio waves. Microwaves are used to heat up your food as well as radar.
- Infrared has shorter wavelengths than microwaves and higher frequencies. Infrared means “below red.” Infrared is used in thermograms or thermal imaging and remote controls. Part of the mid-range.
- Visible light is the only type of electromagnetic radiation that we can see. The waves have shorter wavelengths and higher frequencies than infrared. It is the narrowest part of the EM spectrum. Part of the mid-range.
- Ultraviolet rays have shorter wavelengths and higher frequencies than visible light. Ultraviolet means “above violet.” Ultraviolet light is often used in medical practices and is the radiation from the sun that we shield ourselves from using sunscreen. Part of the mid-range
- X-rays have shorter wavelengths than ultraviolet rays and higher frequencies. X-rays can pass through some forms of matter such as skin but it cannot penetrate through bone due to its density. It is absorbed instead.
- Gamma rays have the shortest wavelengths and the highest frequencies of any other type of radiation on the EM spectrum which means they have the highest energy. They are dangerous but also in treating some types of cancer