Light and Optics Flashcards
Equation: Speed of light in a vacuum
c = wavelength * frequency
Wavelength and frequency are ________ proportional. So a _______ wavelength implies a _______ frequency.
inversely
longer wavelength
lower frequency
Equation: Index of Refraction
n = c / v
Note: n = angle of refraction; c = speed of light through a vacuum; v = speed of light in material medium
The impedance of a medium to the passage of light
index of refraction (n)
index of refraction in a vacuum
n = 1
speed of light in a material medium
v
T/F: v < c and n > 1 for all media except in a vacuum
True
as light travels from one medium into another, the frequency does not change but the _______ and the ______ will
wavelength and the speed
Law of Reflection
ø incidence = ø reflection
angle of incidence always equals the angle of reflection
When drawing a line “Normal” to the surface of a refracting material, always draw the line ______ to the interface. Define the angles from the normal to the ray.
perpendicular
Equation: Snell’s Law
n1 * sin(ø1) = n2 * sin(ø2)
Note: n1 and n2 are indices of refraction for the appropriate medium; ø1 and ø2 are the angles between the refracted rays and the “normal”
Usually, when light crosses a boundary between two media of different indices of refraction, it is partly _______ and partly ________
reflected and partly refracted
When light goes from a medium of high to one of low refractive index, if the angle of incidence is larger than the _________, then all of the light is reflrected
critical angle
Formula: Total internal reflection (critical angle)
sin(ø)crit = n2 / n1
Note: n2 < n1
If n2 is greater than n1, then the light will bend ________ normal
towards the Normal
If n2 is < n1, light bends ________ from normal
away from Normal
a concave mirror is _______
converging
a concave lens is ________
diverging
a convex mirror is ________
diverging
convex lens is __________
converging
Equation: Focal Length
*(mirrors and lenses)
1/f = 1/do + 1/di
Note: 1 / focal length = 1/object distance + 1/image distance (from the source)
d(o) is always _____ for a real object
positive
Equation: Magnification
m = -d(i) / d(o)
When magification is > 0, it means that the image is _______
upright
When magnification is < 0, it means that the image is _______
inverted
if the absolute value of magnification |m| > 1, then the image is
an enlarged image
if the absolute value of magnification is < 1, then the image is
a reduced image
if focal length is positive, then the lens/mirror is _______
converging
if the focal length is negative, then the lens/mirror is _______
diverging
if the image distance (di) is positive, then it is a ______
real image
if the image distance (di) is negative, then it is a ________
virtual image
if the object distance (do) is positive, then the object is on the ___________ as light going in
same side
if the object distance (do) is negative, then the object is on the ___________ as light going in
opposite side
For a positive object distance (object on the same side as light going in), m > 0 means that the image distance has to be _______, which means that it has to be virtual
negative
di is negative for a virtual image
______ images are upright (erect)
virtual images
For a positive object distance (object on the same side as light going in), when m < 0, the image distance has to be __________, and the image has to be real.
positive
di is positive for a real image
_______ images are inverted
Real images
