Lect. 8 Light & Optics Flashcards
transverse wave
travelling oscillation of an electric and magnetic field (perpendicular to each other)
direction of propogation is perpendicular to both fields
electromagnetic wave
constant value for each particular wave
= E / B
speed of an electromagnetic wave (c) through a vacuum
a small sliver from the electromagnetic spectrum
includes wavelengths 390 - 700 (*10^-9 nm)
light
“color” / wave in electromagnetic spectrum w/ the highest energy, shortest wavelength, and highest frequency
travels slowest through a medium (700)
violet light
“color” / wave in electromagnetic spectrum w/ the lowest energy, longest wavelength, lowest frequency, travels fastst through a medium (390 nm)
red light
“beyond violet”
just beyond the visible spectrum on the smaller wavelength side; very high in energy
Ultraviolet Light
just beyond visible spectrum on the longer wavelength side; very low in energy
Infrared light
Equation: speed of light (wavelength w/ corresponding frequency)
c = f * wavelength
used to find the speed of light constant through some medium
compares c in a vacuum to c through some medium
Index of Refraction (n)
Equation: index of refraction (n)
n = c / v
All media have an index of refraction (n) ____ than 1.
greater than
A higher index of refraction (n) indicates that a wave moves _______ through the medium
slowly
Index of refraction for water
n (water) = 1.3
Index of refraction for glass
n (glass) = 1.5
light w/ electric fields all oriented in the same direction
plane-polarized light
The dual nature of light states that light acts like a ____ and a _____.
wave and a particle
angle at which a light ray strikes an interface
angle of incidence
angle at which light ray is reflected off an interface
angle of reflection
angle at which a light ray may refract off an interface
ange of incidence = angle of reflection
angle of refraction
Equation: Snell’s Law
-Described angle of Refraction
n1 * sin(ø)1 = n2 * sin(ø)2
Note: n1 and n2 = respective interfacing media; doesn’t matter which is which
When light crosses into a new medium, _____ is constant but ____ changes.
frequency is constant but wavelength changes
If the index of refraction (n) goes up, light slows down and ______ shortens
wavelength
If the index of refraction (n) goes down, light ______ and wavelength lengthens
speeds up
Equation: Energy of a Photon
E = h * f
Note: h = Planck’s constant