Topic 1-4 Main Knowledge Flashcards
What is EMR?
- EMR is created whenever a charge is accelerated, the acceleration of a charge creates a pulse changing electric and magnetic fields
who created the first mathematical electromagnetic wave theory?
james clerk maxwell
JC Maxwell predicted that EMR should be created when….
an electric charge is accelerated/oscillated
ROYGBIV
red
orange
yellow
green
indigo
violet
most accurate way to measure speed of light
michelson; using a rotating mirror and a fixed mirror separated by a large distance. A light source projects light onto a rotating mirror. The reflected light then travels to the fixed mirror and back again. The time is measured by the rotation of the mirror
reflection wave
when a wave is directed back into the medium after hitting the boundary to another medium
law of reflection
where angle of reflection is equal to angle of incidence
refraction
bending of light due to light changing speed as it goes from one medium to another
high index to low index
light bends away from normal
low index to high index
light bends towards normal
total internal reflection
waves arriving at the interface/boundary from one medium to another (e.g., from water to air) are not refracted into the second (“external”) medium, but completely reflected back into the first (“internal”) medium.
Mirrors are either classified as
concave or convex
a concave mirror
reflects parallel ray inward the principal axis and the focus
a convex mirror
reflects parallel rays outward away from the principal axis and focus
a ray that is parallel to the principal axis will be
reflected toward or away from the focal point
a ray going through the focal point or toward the will focal point will
be reflected parallel to the principal axis
real image
one that is formed on the side where the eye is placed for viewing, formed by “real” light rays —> can be projected onto a screen and are upside down
virtual image
is on the opposite side to your eye, these are formed by “virtual” light rays —-> cannot be projected onto a screen and appear upright
lens can be classified as either
converging or diverging
converging lens
aka convex lens, refracts parallel rays inward toward the principal axis and focus
diverging lens
aka concave lens refracts parallel rays outward away from the principal axis and the focus
distance in thin lens equation
- real focal points or images = positive
- virtual focal points or images = negative
height in thin lens equation
- upright images = positive
- inverted images = negative
The 7 wavelength EMR waves
radio = 10^3 and F:10^4
Microwave = 10^-2 and F: 10^8
infrared = 10^-5 and F: 10^12
visible = .5 x 10^-6 and F: 10^15
ultraviolet = 10^-8 and F:10^16
x ray =10^-10 and F: 10^18
gamma ray = 10^-12 and F: 10^20
