light | gen physics ii

light

the form of energy that makes it possible to see things : the brightness produced by the sun, by fire, by a lamp, etc.

Isaac Newton

wrote and published several papers on properties of light and colors; advocated corpuscular theory of light and published Opticks in 1709

corpuscular theory

states that light is made up of a stream of small particles referred to as corpuscles

Christiaan Huygens

studied the properties of light and proposed the wave theory of light in his book Traite de la lumiere in 1678

Thomas Young

partially proved the wave theory of light using the double slits experiment

wave-particle duality

states that light can be described as either a particle or a wave

double slits experiment

demonstrates, with unparalleled strangeness, that little particles of matter have something of a wave about them, and suggests that the very act of observing a particle has a dramatic effect on its behavior

destructive interference

occurs when waves come together so that they completely cancel each other out (e.g. crest to trough)

constructive interference

When two waves travel in the same direction and are in phase with each other, their amplitude gets added, and the resultant wave is obtained (e.g. crest to crest)

quantum mechanics

the field of physics that explains how extremely small objects simultaneously have the characteristics of both particles (tiny pieces of matter) and waves (a disturbance or variation that transfers energy)

electromagnetic spectrum

the entire distribution of electromagnetic radiation according to frequency or wavelength

true

TRUE OR FALSE: Light waves are electromagnetic waves which do not require a medium to travel from one place to another

radio, microwave, infrared, visible, ultraviolet, x-rays, gamma

types of electromagnetic radiation

radio waves

have the longest wavelength and the shortest frequency; commonly used in communication

microwaves

the EM waves often used for cooking microwavable foods like popcorn

infrared waves

EM waves that are often detected in the form of heat

visible light

a small band of light that is visible to the human eye

ultraviolet light

the radiation emitted by the sun and is the reason why people get skin tans when exposed too long under the sun

x-rays

high energy EM waves which can penetrate the skin and are often used by doctors to produce images to examine bone fractures

gamma rays

have the shortest wavelength and greatest frequency among the EM waves

dispersion

process of white light splitting into its constituent colors

law of reflection

when a light ray strikes the reflecting surface at a certain angle with respect to the normal, that light ray will also be reflected at the same angle on which it struck the surface

diffuse reflection

reflection from a rough, texture surface such as paper or unpolished wood

specular reflection

reflection from a smooth, shiny surface such as a mirror or a water surface

refraction

the bending of a wave when it enters a medium where its speed is different

optical density

describes the tendency of a material to preserve the energy of a light ray before it travels to another medium; can be indicated by determining the index of refraction

total internal reflection

when the angle of refraction is at 90° or greater, so the total light is reflected back into the original material and no light enters the new material

critical angle

the angle on which the incident ray experiences a total internal reflection

Snell’s Law

formulated by Willebrord Snellius; describes how light refracts when passing from one medium to another with a different refractive index

polarization

a property of transverse waves which specifies the geometrical orientation of the oscillations

unpolarized light

light waves that vibrate in more than one plane

polarized light waves

are light waves in which the vibrations occur in a single plane

analyzer

used to check whether the light has been polarized or not