Lec 7 Flashcards
Radiation
The flow of electromagnetic energy (in waves’)
What are the 7 catagones of radiation?
Visible light
X -rays
Uv light
Gamma Rays
Infrared
Microwaves
Radio wanes
What is electromagnetic radiation)
Energy that travels in wave form
Holds inverse relationship to frequency
- small wave length-high frequency
How is energy related to wave frequency? (Electro mag )
High frequency= high energy
How much radiation do objects emit?
An amount proportional to its temp
What is a black body
When a object has an emissivity valve of 1 (100%)
All radiation absorbed is emitted back out
What is emissivity?
A coefficient that defines what proportion of radiation an object receives is emitted.
What is wien’s law used for?
To determine the wave length at which maximum energy emissions occur from an object
Will be expressed in micrometers
What are the 3 ways materials can interact with EMR
Transmitted (E pass through material)
absorbed
Reflected
What is another name for reflection of EMR
Scattering
What are the factors that impact scattering?
- wave length of EMR in relation to particle size.
- ament of particles present (think atmosphere layer)
- had far the EMR travels though the atmosphere.
What are the 3 types of scattering?
Rayleigh
mie
Non selective (geometric)
Rayleigh scattering
When waves shorter than visible spectrum are scattered by particles smaller them the incoming wave lengths
Why the sky is blue. (Blue + purple radiation are short ware and are “traped” in the sky via scattering
mie scattering
When wavelength of EMR interacts with similar sized particles (or larger) in the atmosphere
Driven by the presence of aerosols
Non selective scattering
Scattering of EMR by large! Particles
Primary example: clouds (H2O vapar)
