2. Light and Vision Flashcards
The range of visible light that humans can see, in wavelengths
λ = 400nm - 750nm
Short wavelength photons have _______ energy
________ photons have high energy
Long wavelength photons have _________ energy
_________ photons have low energy
Red corresponds to _____ wavelength and ______ energy of photons
______ corresponds to long-wavelength and low energy of photons
Blue corresponds to ______ wavelength and ______ energy of photons
_______ corresponds to short-wavelength and high energy of photons
Wavelength of typical monochromatic green light
λ = 550 nm
The typical range of light that animals can see, in wavelengths
λ = 300 - 750nm
Near ultra-violet light that only animals can see
300-400 nm
Invisible light with wavelength from 700nm to 1mm is called ______ light
Invisible light with wavelength from ____ to ____ is called infrared light
Invisible light with wavelength from 10nm to 400nm is called _________ light
Invisible light with wavelength from _____ to _____ is called ultraviolet light
What causes a rainbow?
Light is refracted when it enters a drop of water. Because short-wavelength light bends more than long wavelength light upon refraction, we see a _________
Why do we see the sky as blue?
_________________ because of Raleigh scattering on particles much smaller than the wavelength of light, such as molecules of gas. Short-wavelength light is scattered more strongly.
What two kinds of light are partly polarised?
Light scattered in the air and light reflected in the water are both ______________
Insects can use _____________ to navigate
______________ can use partly polarised light for ________________
Describe in one sentence how vision generally works
Light interacts with electrons of visual pigment leading to chemical reactions
Photoreceptor cells contain visual pigment (rhodopsin) which consist of __________ and __________
Photoreceptor cells contain __________ which consist of retinal and a protein (opsin)
Rhodopsin
Visual pigment in a photoreceptor cell
Retinal
Chromophone that absorbs light (in the rhodopsin / visual pigment) of a photoreceptor cell
Opsin
The protein in the visual pigment /rhodopsin of a photoreceptor cell.
Why is the long-wavelength limit on visible light 750nm?
Photons of longer wavelengths than _____ don’t have enough energy for vision. (This is the _________ limit on _____________)
Why is the short-wavelength limit on visible light 300nm?
Proteins absorb light below _____ nm (this is the _______ limit on _________)
Eyes cannot be invisible because ______________
Eyes cannot _________________ because they contain pigment cells
Image formation is ____________________
________________ is transformation of angle of view into a position on light sensitive media
Image formation in compound eyes
Erect image (the same image, but smaller on the eye)
Ommatidia
The units of a compound eye
Why are compound eyes not great optically?
You would need really big eyes for good vision.
Pinhole camera eyes need to be _____ and the pinhole needs to be __________ for good resolution.
___________ eyes need to be large and the _______ needs to be small for good resolution.
Humans have _________ type eyes with _________
___________ have camera-type eyes with dioptric apparatus.
Dioptric apparatus
A lens that focuses light onto the retina
