Lecture 22 (end of exam 2 material) Flashcards
What was the main question 100-150 years ago?
What is light and colour
What spectrum is visible light apart of
Electromagnetic
Light is a _____
wave
All light ____ have the ____ speed
Wave the same
What is the differences in different light?
The distance from peak to peak called wavelength
Wave length and energy are _____ related
inversely
____ the wave length the _____ the energy
Larger , lower
What are the most powerful type of light?
Gamma rays
The human eye can see wavelengths from ____ nm to _____ nm
380 to 740
What colour is 380 nanometers?
purple
What colour is 740 nanometers?
Red
Radio waves have the ____ wave lengths
longest
What are the three things that can happen when light hits matter?
1) Can reflect off
2) Pass through
3) Be absorbed
True or false; Different wavelengths of light react the same to different things
False; react differently
Why do plants look green?
Because plants absorb red and blue light to make glucose and reflect green light
What is just past visible light that has longer wavelengths and less energy?
Infrared light
what is infrared light?
heat
What is just past visible light that has shorter wavelengths and more energy?
Ultra violet light (UV light)
What things is infrared light associated with in the atmosphere?
1) Greenhouse effect
2) Global warming
3) Climate change
What things is UV light associated with in the atmosphere?
1) Production of the ozone
2) Hole in the ozone
What visible color has the lowest energy
red light
Why was there no life on land until 400 million years ago?
Because the UV light would damage and break the DNA of any organism
What are the three types of UV light and what are there wavelengths?
a) UVA : 320-400 nm
b) UVB : 280-320 nm
c) UVC : <280 cm
Which type of UV light is most damaging to tissue and DNA?
UVC
UVC plus oxygen results in what? and where does this occur
2O
in the stratosphere (30-50km above earth surface)
O plus Oxygen results in what?
O3 (The ozone)
O3 (ozone) plus UVB results in what?
O and oxygen
What type of UV light reaches the earth surface and what does it cause?
UVA causes sun tans
Ozone is only seen above the ____
Troposphere
What units do we use to measure the ozone?
Dobson units (DU)
If one removes all the gases but the ozone and then compresses the ozone to 1ATM how thick would the atmosphere be?
3 mm or 300 DU
When was the hole in the ozone first mentioned, in what article and by who
Nature, May of 1985 and by Farman
What did Farman state in his article?
That in September 1984 “suddenly and unexpectedly” The ozone had dropped by 50% and returned 6 weeks later
