Light And Matter Flashcards
Which is more important joules rate
Rate
The energy that light carries is
Radiative energy
The rate of energy flow is called
Power
WAtts are
Units to measure power
1 watt=
I joule/s
Red, blue, and green
Primary colors of vision . Colors ? Detected by cells in my eye .
Diffraction grating
A DVD. A piece of plastic or glass etched with many closely spaced lines. A type of prism.
Light can interact with matter in which 4 ways
RATE Reflect Absorb Transmit Emit
your hand absorbs energy when placed near an incandescent light bulb
True
Transmission
Some matter allows light to pass they it. Glass and air
Light bounces off matter in one direction
Reflection . If it is more then it is scattering .
The angle which light strikes the mirror is
Equal to the angle it is reflected
Movie screens and pages of my book use
Scattering
Transmit light
Transparent
The process by which molecules escape solids.
Sublimation
How is energy stored in atoms
Mass
Kinetic. They are moving
Electrical potential energy. Electron arrangement
The order of light on an electromagnetic spectrum.
Small to large
Radio. Microwave. Infrared. Visible light. Ultraviolet.
X-rays , Gamma rays.
What is the difference between different chemical elements
Number of protons
How do light and matter mix
RATE
Reflection/scattering
Absorption. Hand near light bulb
Transmission some matter (air glass) allows light to pass thru transmit light.
Emission a light bulb emits visible ligjt
An ionized gas
Plasma
What breaks up molecules at very high temps
Molecular dissociation
Strips electrons from atoms
Ionization
When an electron moves from one energy level to another and can only occur when electron loses or gains the exact amount of energy.
Energy level transitions
What are the three types of spectra
Continuous. Rainbow of colors
Absorption lines. Specific colors are missing from rainbow
Emission lines. Only specific colors against black background
How does light tell us what things are made of
every kind of atom, molecules and ion produces an unique set of spectral lines so we can determine composition by studying their lines.
How does light tell us about temperature of stars
They produce thermal radiation spectra. The most common continuous spectra.
Hotter objects produce more total radiation per unit area and emit photons with higher average energy.
Doppler tells us
How fast something is moving towArd or away from us.
Spectral lines are moved to shorter (blue) wavelengths for incoming and red for objects moving away.
Absorb light
Opaque. Sunglasses and clear eyeglasses are a mixture of opaque and transparent .
A telescopes most important properties are
Light collecting area
Angular resolution how much detail we can see in images.
Two basic designs of telescopes
Refracting : bends light through a lens
Reflecting forms image by focusing light with mirrors
