Physics Light Test 1 Flashcards
Luminous Objects
Objects that emit light (create it themselves) like the sun, tv screens, lamps, lazers
Non-luminous Objects
Objects that reflect light from other luminous objects, and don’t make light themselves.
How can you see beams of light?
Due to dust particles, smoke or mist in the air which reflect the light into your eyes.
How do the luminous objects create light?
They radiate energy as visible light.
When is light released?
When atoms within the object absorb the energy and the electrons jump to a higher level of orbit. When they return to their original orbit, light is released.
Diffused light
On surfaces that are not even or smooth, light gets reflected to all different directions.
Regular light
When light gets reflected off of smooth surfaces and into one direction, like the mirror.
Absorption light
Materials which are black absorb the light instead of reflecting it, becoming hotter.
Transmit light
When the light passes right through the materials like glass or water.
Why do white objects seem white?
Because they reflect the emitted light
Why do black objects seem black?
Because they absorb the emitted light and become dark.
Why are some things transparent?
If the vibrational energy of light is passed through an object, then the object will now appear clear.
Rays
Used to show which way the light is going.
How does light travel?
In straight lines
Light transfers energy
Materials gain energy when they absorb light.
What type of waves are light waves?
Transverse waves.
Diffraction
Waves spread out when they pass through a gap.
Better if the gap size is the wavelength size as bigger gaps cause less diffraction.
Photons
Smallest energy particles of light.
Why can light travel through empty spaces?
Because electric and magnetic ripples do not need material to travel through. This is why the light from the sun can reach us.
Speed of light
300 000 000 m / s
Wavelength range
From 0.0004 mm Violet light (shortest WL)
To 0.0007 mm Red Light (longest WL)
Monochromatic Light
Emitted light of a single wavelength and color, like a laser.
White light
Made up of a mixture of wavelengths
Time =
Distance ÷ Speed
