Chapter 10: Light and Optics Flashcards
Electromagnetic waves are transverse or longitudinal?
Transverse; they can also travel through a vacuum
Electromagnetic waves consist of what two oscillating fields?
an oscillating electric field and an oscillating magnetic field; the two fields are perpendicular to each other and to the direction of the propagation of the wave
The electromagnetic spectrum is:
the range of frequencies and wavelengths found in electromagnetic waves
The electromagnetic spectrum from lowest energy to highest energy:
radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays
Equation to determine the wavelength or frequency of light traveling in air or a vacuum:
c = fλ
where c is the speed of light and is equal to 3 X 108;
units = m/s
1 angstrom =
1 X 10-10
Electromagnetic waves vary in frequency and wavelength, but in a vacuum, they all travel at the same speed, which is:
the speed of light (3 X 108 m/s)
The visible spectrum ranges from what wavelengths?
380nm (violet) to 760nm (red)
The order of the colors in the visible spectrum:
ROY-G BIV
red (760nm), orange, yellow, green, blue, indigo, violet (380nm)
Rectilinear propagation:
when light travels in a straight line through a single homogenous medium
Theory of geometrical optics describes:
the behavior of light at the boundary of a medium or interface between two media
Reflection is:
the rebounding of incident light waves at the boundary of a medium
Law of Reflection equation:
θ1 = θ2
where θ1 is the incident angle and θ2 is the reflected angle
the angles are always measured from normal (a line perpendicular to the surface of the medium)
An image is real if:
the light converges at the position of the image
An image is virtual if:
the light appears to be coming from the position of the image, but does not actually converge there
Plane mirrors always create what kinds of images?
virtual, upright images the same size as the object since the light does not converge at all
The two types of spherical mirrors:
concave and convex; they both have centers and radii of curvature as well as focal points
Concave mirrors:
converging systems and can produce real, inverted images or virtual, upright images, depending on the placement of the object relative to focus
Convex mirrors:
diverging systems and will only produce virtual, upright images
The focal point of converging mirrors and converging lenses will always be:
positive
The focal point of diverging mirrors and diverging lenses will always be:
negative
Equation to determine the object or image distance from a mirror, focal length, or radius of curvature:
1/o + 1/i = 1/f = 2/r
where o is the distance of the object from the mirror, i is the distance of the image from the mirror, f is the distance from the focal point to the mirror (focal length), and r is the distance between the center of curvature and the mirror (for spherical mirrors)
units = m-1
For spherical mirrors, what does the focal length (f) equal?
f = r/2