Lights and Optics (8)

Electromagnetic Waves

are transverse waves that consist of an oscillating electric field and oscillating magnetic field

Perpendicular

the electric and magnetic fields of electromagnetic waves are ___________ to each other and to the direction of propagation of the wave

Electromagnetic Spectrum

is the range of frequencies and wavelengths found in EM waves

Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, and Gamma-rays

the EM spectrum includes, from lowest to highest energy:

Visible Spectrum

runs from approximately 400 nm (violet) to 700 nm (red)

Reflection

is the rebounding of incident light waves at the boundary of a medium

Law of Reflection

states that the incident angle will equal the angle of reflection, as measured from the normal

Spherical Mirrors

have centers and radii of curvature, as well as focal points

Concave Mirrors

are converging systems and can produce real, inverted images or virtual, upright images, depending on the placement of the object relative to the focal point

Convex Mirrors

are diverging systems and will only produce virtual, upright images

Plane Mirrors

also produce virtual, upright images; these images are always the same size as the object. They may be thought of as spherical mirrors with infinite radii of curvature

Refraction

is the bending of light as it passes from one medium to another. The speed of light changes depending on the index of this of the medium. This speed change causes this

Dispersion

the amount of refraction depends on the wavelength of the light involved; this behavior causes ______ of light through a prism

Snell’s Law (Law of Refraction)

states that there is an inverse relationship between the index of refraction and the sine of the angle of refraction (measured form the normal)

Total Internal Reflection

occurs when light cannot be refracted out of a medium and is instead reflected back inside the medium. This happens when light moves from a medium with a higher index of refraction to a medium with a lower index of refraction with a high incident angle

Critical Angle

the minimum incident angle at which total internal reflection occurs

Lenses

refract light to form images of objects

Lensmaker’s Equation

lenses with non negligible thickness require use of this

o > 2f

converging systems; real, inverted, reduced image

o = 2f

converging systems; real, inverted, same image

2f > o > f

converging systems; real, inverted, magnified image

o = f

converging systems; no image

o < f

converging systems; virtual, upright, magnified image

all object distances

diverging systems; virtual, upright, reduced

Diffraction

is the bending and spreading out of light waves as they pass through a narrow slit. This may produce a large central light fringe surrounded by alternating light and dark fringes with the addition of a lens

Young’s Double-slit Experiment

shows the constructive and destructive interference of waves that occur as light passes through parallel slits, resulting in minima (dark fringes) and maxima (bright fringes) of intensity

Plane-polarized Light

in this, all of the light rays have electric fields with parallel orientation

Polarizer

plane-polarized light is created by passing unpolarized light through this

Circularly Polarized Light

in this, all of the light rays have electric fields with equal intensity but constantly rotating direction. This is created by exposing unpolarized light to special pigments or filters