Lec 8 Flashcards
Why does light refract
When light travels through a medium with a higher density than air, it moves slower causing the illusion that an object is displaced
Which light is bent the most? The least?
Most= purple
Least-red
What is needed to see a rainbow
Light and the correct orientation with respect to the medium its passing through
What is a mirage
The illusion that water is on the grand (in the distance) due to the temp difference (and density) between the air and air right against the surface.
This allows objects to appear reflected
Inverse square law
The further away we are from a body editing energy, the less energy we will receive as it is spread over a larger area
Cuss concentrated
Solar constant
1378 W/m2
Measured at the top of the atmosphere
Is the solar constant actually constant?
No.it is dependant on the earths position to the son in its orbit. Since the orbit is circular and it changes over time, SE does the constant.
Zenith angel
How many degrees the sun is away from a 90° angle
Altitude angle
The angle/how far away the sen is from oº (herizen)
When does an area recipe maximum radiation?
When the sun is directly over head
- zenith = 0°
- atituted= 90°
This is because of less scattering of light and a lesser effect of the inverse square law
How do seasons (earths position in orbit) impactamount of radiation retired
Earths tilt is also considered here.
During “summer” the suns rays are perpendicular to the northern hemisphere (tropic of cancer)
Dunno “winter” the sunrays are perpendicular to the tropic of Capricorn in the south
Summer solstice
Sun is over the Tropic of Cancer
Low zenith angles in the north
Autumnal equinox
Sept 22
Equal amounts of sunlight everywhere
The sun hits the equator
Vernal equinox
Sun is over equator
Same amants of sun everywhere (12 hours)
March 20
Winter solstice
North Pole is pointed away from sun, so the sun is directly over head the Tropic of Capricorn
North has the highest zenith angle at this time
