Unit 7- The E/M Spectrum Flashcards
How are mechanical waves created?
Vibration
Are mechanical waves transverse or longitudinal?
Both
True or false: mechanical waves carry energy
True
What does a mechanical wave require to be classified as a mechanical wave?
A medium
Is light a mechanical or an electromagnetic wave?
Electromagnetic
Produced when an electric charge vibrates up and down or accelerates
Electromagnetic wave
What are the two parts that make up an electromagnetic wave?
Electric field and magnetic field
True or false: the electric and magnetic field regenerate eachother
True
True or false: electromagnetic waves needs a medium to travel through
False
What type of energy do electromagnetic waves carry?
Radiation energy
What is the speed of sound?
343 M/s
What is the speed of light?
300,000,000 M/s or 3x10(8)
Both sound and light use what equation?
Wave equation V=f(wavelength)
Who is Michelson?
Accurately measured the speed of light
Who is Newton?
Proposed light travelled as a particle
Who is Young?
Discovered interference and saw that it happens with waves, so light must be a wave
Who is Einstein?
Found the photoelectric effect
How do photons travel?
In all directions away from light, they spread out a way from the source.
Who is Herschel?
First guy to study the E/M spectrum
Is red or blue light warmer?
Red light
What is a Radio Wave?
Longest wavelength, but shortest frequency
What are TV waves?
Radio waves that also carry info for pictures.
What are Microwaves?
Highest frequency radio waves, cell phones use microwaves.
What is Radar?
Uses short burst of radio waves, then they change frequency when they hit objects and bounce back.
What is Infrared (IR)?
Invisible to the human eye, if objects are hot they give off more IR.
What is Visible light?
The only part of the EM spectrum we can see.
What is Ultraviolet light?
Bad for skin in large doses, can cause cancer.
What is X-ray?
High energy to penetrate objects, see inside human body.
What is Gamma?
Highest energy waves and frequency, lowest wavelength. Used to kill cancer cells.
What materials can be classified as?
Transparent, translucent, opaque
What is transparency?
Let’s all light through
What is Translucent?
Let’s some light through, make objects look “fuzzy”
What is opaque?
Doesn’t let any light through.
What happens when a light strikes a material?
Reflected, absorbed or transmitted.
How is light reflected?
Takes parallel light rays and reflects them in predictable ways.
How is light transmitted?
Refraction, polarization and scattering
What’s refraction?
Rays of light bend
What is white light consisted of?
All the colors, (ROYGBIV).
What is polarization?
Unpolarized light vibrates in all directions, then polarized light chops off the vibrations.
If an object is red, what colors are absorbed?
Every color but red.
What happens when you send light through a prism?
It refracts/bends.
What is Dispersion?
When light bends/refracts.
Primary colors for mixing light?
Red, Green, Blue
Secondary colors for mixing lights?
Cyan, Magenta, Yellow
How is light made?
Electrons jump energy levels after absorbing energy. They emit photons.
What are incandescent bulbs?
Regular bulbs, argon doesn’t react with the filament allowing it to last a long time.
What is Filament?
Thin coil of wire that gets very hot when electrons pass through
What is in the inside of a fluorescent bulbs?
Phosphors that emits light.
What is laser light?
The light is coherent.
What is neon light?
He (pink), Ne (red), Krypton (violet)
What are sodium vapor lights?
Very bright and efficient, usually street lights
What are tungsten-halogen lights?
Like incandescent bulbs, with different gases.