Ch 8 - Light and Optics Flashcards Preview

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Flashcards in Ch 8 - Light and Optics Deck (73)
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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



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



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



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


what happens if image is |m| = 1

image is same size as object