21 terms #1

X-rays

an electromagnetic wave of high energy and very short wavelength, which is able to pass through many materials opaque to light

Microwaves

an electromagnetic wave with a wavelength in the range 0.001-0.3 m, shorter than that of a normal radio wave but longer than those of infrared radiation. Microwaves are used in radar, in communications, and for heating in microwave ovens and in various industrial processes. short for microwave oven. verb

Gamma rays

penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei.

Collin Kenny

period 7

Nearsighted

unable to see things clearly unless they are relatively close to the eyes, owing to the focusing of rays of light by the eye at a point in front of the retina; myopic.

Farsighted

unable to see things clearly, especially if they are relatively close to the eyes, owing to the focusing of rays of light by the eye at a point behind the retina; hyperopic.

Concave lens

A concave lens is a lens that possesses at least one surface that curves inwards. It is a diverging lens, meaning that it spreads out light rays that have been refracted through it. A concave lens is thinner at its centre than at its edges, and is used to correct short-sightedness.

. Convex lens

A convex lens is a converging lens. When parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus. The distance between the principal focus and the centre of the lens is called the focal length.

Translucent material

A translucent material lets light pass through, but objects on the other side can't be seen clearly. Think Shrinky Dinks or stained glass. In contrast, a transparent material allows you to clearly see the objects on the other side. Frosted glass is translucent, and regular glass is transparent.

Visible light

Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 700 nm. In terms of frequency, this corresponds to a band in the vicinity of 430-770 THz.

Opaque material

In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc. An opaque object is neither transparent (allowing all light to pass through) nor translucent.

Infrared rays

Infrared radiation is a type of electromagnetic radiation, as are radio waves, ultraviolet radiation, X-rays and microwaves. Infrared light is the part of the EM spectrum that people encounter most in everyday life, although much of it goes unnoticed. It is invisible to human eyes, but people can feel it as heat.

Transparent material

Materials that allow the transmission of light waves through them are called optically transparent. Chemically window glass and clean river or spring water are prime examples of this. Materials which do not allow the transmission of any light wave frequencies are called opaque.

Index of refraction

The index of refraction is defined as the speed of light in vacuum divided by the speed of light in the medium. The indices of refraction of some common substances are given below with a more complete description of the indices for optical glasses given elsewhere.

Ultraviolet rays

Ultraviolet light is a form of radiation which is not visible to the human eye. It's in an invisible part of the "electromagnetic spectrum". Radiated energy, or radiation, is given off by many objects: a light bulb, a crackling fire, and stars are some examples of objects which emit radiation.

Iris

a flat, colored, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the center.

Retina

a layer at the back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed. orgin

Lens

a piece of glass or other transparent substance with curved sides for concentrating or dispersing light rays, used singly or with other lenses.

Pupil

a soft, wet, shapeless mass of material.

. Radio waves

an electromagnetic wave of a frequency between about 104 and 1011 or 1012 Hz, as used for long-distance communication

Optic nerve

each of the second pair of cranial nerves, transmitting impulses to the brain from the retina at the back of the eye.

Electromagnetic spectrum

electromagnetic radiation is classified by wavelength into radio wave, microwave, terahertz. radiation, infrared, the visible region that is perceived as light, ultraviolet, X-rays and gamma rays. The behavior of EM radiation depends on its wavelength.

Cornea

the rarefied gaseous envelope of the sun and other stars. The sun's corona is normally visible only during a total solar eclipse when it is seen as an irregularly shaped pearly glow surrounding the darkened disk of the moon.