Ch 8 - Light and Optics Flashcards
electromagnetic spectrum from lowest energy to highest energy
radio waves (wavelength range from 10^9 - 1 m), microwaves (1 m - 1 mm), infrared (1 mm - 700 nm), visible light (700 nm - 400 nm), ultraviolet (400 - 50 nm), x-rays (50 - 10^-2 nm), gamma rays (less than 10^-2 nm)
electromagnetic waves
transverse waves - oscillating electric and magnetic field vectors are perpendicular to the direction of propagation and each field is perpendicular to each other.
common units of wavelength
mm (10^-3 m), fancy um (mu) (10^-6 m), nm (10^9 m) and A with a circle at the point (angstrom, 10^-10 m)
visible spectrum from lowest to highest energy
Red, orange, yellow, green, blue, violet (roy g bv)
speed of light
EM waves travel this fast in a vacuum and in air: c = 3.00 x 10^8 m/s
equation for speed of light
c = f x wavelength; f = frequency; c = speed of light in air and vacuum
approximate wavelength boundaries of the visible spectrum
400-700 nm
blackbody
ideal absorber of all wavelengths of light, which would appear completely back if it were at a lower temp than its surroundings
rectilinear propagation
concept that light travelling through a homogenous medium will travel in a straight line
reflection
rebounding of incident light waves at the boundary of a medium
law of reflection
theta sub 1 = theta sub 2 (angles of reflection); theta sub 1 = angle of incident and theta sub 2 = reflected angle
normal (in reference to reflection)
a line drawn perpendicular to the boundary of a medium; all angles in optics are measured from the normal, not the surface of the medium
real image
image in which the light actually converges at the position of the image; this image can be projected onto a screen
virtual image
image in which the light only appears to be coming from the position of the image but does not actually converge there
plane mirrors
flat reflective surfaces that cause neither convergence nor divergence of reflected light rays; because light does not converge at all, these always created virtual images because reflected light remains in front of the mirror but the image appears behind the mirror
spherical mirrors
come in two varieties: concave and convex and have associated center of curvature (C) and radius of curvature (r)
center of curvature
point on the optical axis located at a distance equal to the radius of curvature from the vertex of the mirror; the center of the spherically shaped mirror if it were a complete sphere
concave mirror
also called converging mirrors; edges coming towards you; center of curvature and radius of curvature are located in front of the mirror
convex
also called diverging mirrors; surface coming towards you; edges away; center of curvature and radius of curvature are behind the mirror
focal length (f) of mirror
distance between focal point (F) and mirror
focal length for spherical mirror
f = r/2 where radius of curvature (r) is distance between C (center of curvature) and the mirror
relationship between four important distances of spherical mirrors
1/f = 1/o + 1/i = 2/r; where f = focal length, o = distance between object and mirror, i = distance between image and mirror, r = radius of curvature
image distance greater than 0
real image which implies that the image is in front of the mirror
image distance less than 0
virtual image; image is behind the mirror
magnification (m)
dimensionless value that is the ratio of the image distance to the object distance (m = -i/o); also gives ratio of the size of the image to the size of the object
inverted image
negative magnification value
upright image
positive magnification value
what happens to image where |m| < 1
image is smaller than object
what happens to image if |m| > 1
image is larger than the object