Exam 1 Concepts Flashcards
Units of monochromatic (or spectral) irradiance
Wm^(-2)μm^(-1)
Units of monochromatic (or spectral) radiance
Wm^(-2)μm^(-1)str^(-1)
Another term for flux density
Irradiance
Another term for intensity
Radiance
Mathematical definition (formula) for a solid angle
Ω = surface area/r^2 (in stradians)
What does the Poyting vector tell us?
It tells us what direction and magnitude the electromagnetic radiation energy is travelling away from the source.
What is the speed of x-rays in a vacuum?
Speed of light: 3.00*10^8 m/s
What is the speed of UV radiation in a vacuum?
Speed of light: 3.00*10^8 m/s
What is the speed of radio waves in a vacuum?
Speed of light: 3.00*10^8 m/s
In terms of sine and cosine, what does e^(iθ) equal?
e^(iθ) = cos(θ) + isin(θ)
Most energetic to the least energetic in the electromagnetic spectrum
Gamma rays, x-rays, UV rays, Visible, IR, Microwaves, Radio (Great Xanax Universally Visualizes Imaginary Monkeys Running)
What is the fraction of the solar output for Visible light?
39%
What is the fraction of the solar output for Thermal IR?
0.9%
What is the fraction of the solar output for UV-A?
6.2%
What is the fraction of the solar output for Near IR?
52%
What atmospheric processes is the Visible region associated?
Mostly transparent atmosphere
What atmospheric processes is the Thermal IR region associated?
Absorbed by water vapor
What atmospheric processes is the X-rays region associated?
Photoionizes all species; upper absorbed atmosphere
What atmospheric processes is the Extreme UV region associated?
Photoionizes O2 and N2; absorbed at 90 km
What atmospheric processes is the Far UV region associated?
Photodissociates O2; absorbed at 50 km
Write the Eulerian representation of plane harmonic waves (the general formula for a plane harmonic wave, not an EM specific solution)?
e^[i(kx-ωt)]
What is the meaning of I/βa
The distance needed to be traveled for the wave’s energy to be attenuated e^(-1) (approximately 37%) of its original.
What is the mathematical relationship (formula) relating frequency and angular frequency?
ω = 2πr
where ω = angular frequency
r = frequency
What is the plane wave solution for a complex electric field using the complex wave vector?
Evector = Enotexp[i(kvector*xvector + ωt)]
What are the three major differences between classical physics and modern physics?
- Classical physics is deterministic, while modern physics is probabilistic.
- Classical physics has continuous energy levels, while modern physics has discrete energy levels.
- In classical physics, a wave is a wave and a particle is a particle. In modern physics, a wave can have particle-like properties and a particle can have wave-like properties.
What is the importance of EM radiation in weather and climate forecast models?
Electromagnetic radiation is constantly/continuously flowing through our atmosphere, making it imperative for our weather and climate models. Diabatic heating on nonlocal processes, also can cause issues calculating atmospheric conditions using radiation.
What are three main assumptions of classical physics (I gave you six)?
- Determinism: If you know the whereabouts of a molecule at time t, you can figure out where it will be in the past or present.
- The properties of light are verified through Maxwell’s electromagnetic wave theory.
- A wave and a particle can only exist on their own. A wave is a wave, and a particle is a particle.
For what did Einstein win the Nobel Prize in Physics?
His paper on the Photoelectric Effect in 1905.
Choose two of Maxwell’s equations for electromagnetic radiation and give a written (not formula) description of those two equations. As an example: The divergence of the Sasquatch field is equal to the negative of the time rate of change of the curl of the Loch Ness Monster field.
- The divergence of the electric displacement equals the density of electric charge.
- The divergence of the magnetic induction equals zero.
- The voltage accumulated around a closed circuit is proportional to the time rate of change of the magnetic flux it encloses.
- Electric circuits and changes in electric fields are proportional to the magnetic field circulating about the area they pierce.
