Chapter 4: Light and Telescopes Flashcards
Light moves at approximately _____ km/s through the vacuum of space (constant).
300,000
Kinetic energy
energy of moving objects
thermal energy
sum of all the kinetic energy of the moving bits of matter inside a substance
Light waves do not require a medium - they can move through the vacuum of empty space. T or F?
True
Speed of a wave (v) =
wavelength (lambda) x frequency (f)
The speed of light in a vacuum is always __
c
What type of wave would a light wave classify as?
transverse wave
Photon
particle of light, carries energy
πΈ=βπ, What is h?
β is Planckβs constant (proportionality between energy and frequency)
h = 6.63 x 10-34 joule-seconds
High energy light is what colour? Low energy light is what colour?
high - blue (less photons)
low - red (more photons)
Name all 7 wavelengths in the electromagnetic spectrum in order of shortest to longest wavelength.
gamma rays, x-rays, UV radiation, visible light, infrared radiation, microwave radiation, radio waves
Within visible light, name all 7 wavelengths in order of shortest to longest wavelength.
violet, indigo, blue, green, yellow, orange, red
Photons are collected by your retina. Three important factors:
Integration factor β how long the instrument records photons into one image (about 0.1 seconds for the eye)
Quantum efficiency β how many photons must strike the instrument to trigger a response (about 10 photons in 0.1 seconds to trigger a single response (up to around 10%) for the eye)
Angular resolution β how close can two points of light be for the instrument to interpret them as separate (about 1 arcminute, or about 1/30 of the diameter of the full moon, for the eye)
When does reflection occur?
as light hits a mirror and bounces off.
When does refraction occur?
when light enters/leaves a material.
