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The relationship among the speed of propagation, wavelength, and frequency for any wave is given byvW=fλvW=fλ, so that for electromagnetic waves,c=fλ,c=fλ,whereffis the frequency,λλis the wavelength, andccis the speed of light. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
The electromagnetic spectrum is separated into many categories and subcategories, based on the frequency and wavelength, source, and uses of the electromagnetic waves. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
Any electromagnetic wave produced by currents in wires is classified as a radio wave, the lowest frequency electromagnetic waves. Radio waves are divided into many types, depending on their applications, ranging up to microwaves at their highest frequencies. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
Infrared radiation lies below visible light in frequency and is produced by thermal motion and the vibration and rotation of atoms and molecules. Infraredâs lower frequencies overlap with the highest-frequency microwaves. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
Visible light is largely produced by electronic transitions in atoms and molecules, and is defined as being detectable by the human eye. Its colors vary with frequency, from red at the lowest to violet at the highest. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
Ultraviolet radiation starts with frequencies just above violet in the visible range and is produced primarily by electronic transitions in atoms and molecules. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
X-rays are created in high-voltage discharges and by electron bombardment of metal targets. Their lowest frequencies overlap the ultraviolet range but extend to much higher values, overlapping at the high end with gamma rays. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
Gamma rays are nuclear in origin and are defined to include the highest-frequency electromagnetic radiation of any type. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
The energy carried by any wave is proportional to its amplitude squared. For electromagnetic waves, this means intensity can be expressed asIave=cε0E022,Iave=cε0E022,whereIaveIaveis the average intensity inW/m2W/m2, andE0E0is the maximum electric field strength of a continuous sinusoidal wave. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
whereIaveIaveis the average intensity inW/m2W/m2, andE0E0is the maximum electric field strength of a continuous sinusoidal wave. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
This can also be expressed in terms of the maximum magnetic field strengthB0B0asIave=cB022μ0Iave=cB022μ0and in terms of both electric and magnetic fields asIave=E0B02μ0.Iave=E0B02μ0. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
and in terms of both electric and magnetic fields as | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
The three expressions forIaveIaveare all equivalent. | https://openstax.org/books/college-physics-2e/pages/24-section-summary |
converging lens : a convex lens in which light rays that enter it parallel to its axis converge at a single point on the opposite side | https://openstax.org/books/college-physics-2e/pages/25-glossary |
converging mirror : a concave mirror in which light rays that strike it parallel to its axis converge at one or more points along the axis | https://openstax.org/books/college-physics-2e/pages/25-glossary |
corner reflector : an object consisting of two mutually perpendicular reflecting surfaces, so that the light that enters is reflected back exactly parallel to the direction from which it came | https://openstax.org/books/college-physics-2e/pages/25-glossary |
critical angle : incident angle that produces an angle of refraction of90º90º | https://openstax.org/books/college-physics-2e/pages/25-glossary |
dispersion : spreading of white light into its full spectrum of wavelengths | https://openstax.org/books/college-physics-2e/pages/25-glossary |
diverging lens : a concave lens in which light rays that enter it parallel to its axis bend away (diverge) from its axis | https://openstax.org/books/college-physics-2e/pages/25-glossary |
diverging mirror : a convex mirror in which light rays that strike it parallel to its axis bend away (diverge) from its axis | https://openstax.org/books/college-physics-2e/pages/25-glossary |
fiber optics : transmission of light down fibers of plastic or glass, applying the principle of total internal reflection | https://openstax.org/books/college-physics-2e/pages/25-glossary |
focal length : distance from the center of a lens or curved mirror to its focal point | https://openstax.org/books/college-physics-2e/pages/25-glossary |
focal point : for a converging lens or mirror, the point at which converging light rays cross; for a diverging lens or mirror, the point from which diverging light rays appear to originate | https://openstax.org/books/college-physics-2e/pages/25-glossary |
geometric optics : part of optics dealing with the ray aspect of light | https://openstax.org/books/college-physics-2e/pages/25-glossary |
index of refraction : for a material, the ratio of the speed of light in vacuum to that in the material | https://openstax.org/books/college-physics-2e/pages/25-glossary |
law of reflection : angle of reflection equals the angle of incidence | https://openstax.org/books/college-physics-2e/pages/25-glossary |
law of reflection : angle of reflection equals the angle of incidence | https://openstax.org/books/college-physics-2e/pages/25-glossary |
magnification : ratio of image height to object height | https://openstax.org/books/college-physics-2e/pages/25-glossary |
mirror : smooth surface that reflects light at specific angles, forming an image of the person or object in front of it | https://openstax.org/books/college-physics-2e/pages/25-glossary |
power : inverse of focal length | https://openstax.org/books/college-physics-2e/pages/25-glossary |
rainbow : dispersion of sunlight into a continuous distribution of colors according to wavelength, produced by the refraction and reflection of sunlight by water droplets in the sky | https://openstax.org/books/college-physics-2e/pages/25-glossary |
ray : straight line that originates at some point | https://openstax.org/books/college-physics-2e/pages/25-glossary |
real image : image that can be projected | https://openstax.org/books/college-physics-2e/pages/25-glossary |
refraction : changing of a light rayâs direction when it passes through variations in matter | https://openstax.org/books/college-physics-2e/pages/25-glossary |
virtual image : image that cannot be projected | https://openstax.org/books/college-physics-2e/pages/25-glossary |
zircon : natural gemstone with a large index of refraction | https://openstax.org/books/college-physics-2e/pages/25-glossary |
A straight line that originates at some point is called a ray. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The part of optics dealing with the ray aspect of light is called geometric optics. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Light can travel in three ways from a source to another location: (1) directly from the source through empty space; (2) through various media; (3) after being reflected from a mirror. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The angle of reflection equals the angle of incidence. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
A mirror has a smooth surface and reflects light at specific angles. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Light is diffused when it reflects from a rough surface. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Mirror images can be photographed and videotaped by instruments. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The changing of a light rayâs direction when it passes through variations in matter is called refraction. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The speed of light in vacuumc=2.99792458Ã108m/sâ3.00Ã108m/s.c=2.99792458Ã108m/sâ3.00Ã108m/s. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Index of refractionn=cvn=cv, wherevvis the speed of light in the material,ccis the speed of light in vacuum, andnnis the index of refraction. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Snellâs law, the law of refraction, is stated in equation form asn1sinθ1=n2sinθ2n1sinθ1=n2sinθ2. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The incident angle that produces an angle of refraction of90º90ºis called critical angle. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Total internal reflection is a phenomenon that occurs at the boundary between two mediums, such that if the incident angle in the first medium is greater than the critical angle, then all the light is reflected back into that medium. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Fiber optics involves the transmission of light down fibers of plastic or glass, applying the principle of total internal reflection. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Endoscopes are used to explore the body through various orifices or minor incisions, based on the transmission of light through optical fibers. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Cladding prevents light from being transmitted between fibers in a bundle. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Diamonds sparkle due to total internal reflection coupled with a large index of refraction. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The spreading of white light into its full spectrum of wavelengths is called dispersion. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Rainbows are produced by a combination of refraction and reflection and involve the dispersion of sunlight into a continuous distribution of colors. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Dispersion produces beautiful rainbows but also causes problems in certain optical systems. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Light rays entering a converging lens parallel to its axis cross one another at a single point on the opposite side. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
For a converging lens, the focal point is the point at which converging light rays cross; for a diverging lens, the focal point is the point from which diverging light rays appear to originate. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The distance from the center of the lens to its focal point is called the focal lengthff. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
PowerPPof a lens is defined to be the inverse of its focal length,P=1fP=1f. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
A lens that causes the light rays to bend away from its axis is called a diverging lens. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Ray tracing is the technique of graphically determining the paths that light rays take. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The image in which light rays from one point on the object actually cross at the location of the image and can be projected onto a screen, a piece of film, or the retina of an eye is called a real image. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Thin lens equations are1do+1di=1f1do+1di=1fandhiho=âdido=mhiho=âdido=m(magnification). | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The distance of the image from the center of the lens is called image distance. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
An image that is on the same side of the lens as the object and cannot be projected on a screen is called a virtual image. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
The characteristics of an image formed by a flat mirror are: (a) The image and object are the same distance from the mirror, (b) The image is a virtual image, and (c) The image is situated behind the mirror. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
Image length is half the radius of curvature.f=R2f=R2 | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
A convex mirror is a diverging mirror and forms only one type of image, namely a virtual image. | https://openstax.org/books/college-physics-2e/pages/25-section-summary |
aberration : failure of rays to converge at one focus because of limitations or defects in a lens or mirror | https://openstax.org/books/college-physics-2e/pages/26-glossary |
accommodation : the ability of the eye to adjust its focal length is known as accommodation | https://openstax.org/books/college-physics-2e/pages/26-glossary |
adaptive optics : optical technology in which computers adjust the lenses and mirrors in a device to correct for image distortions | https://openstax.org/books/college-physics-2e/pages/26-glossary |
angular magnification : a ratio related to the focal lengths of the objective and eyepiece and given asM=âfofeM=âfofe | https://openstax.org/books/college-physics-2e/pages/26-glossary |
astigmatism : the result of an inability of the cornea to properly focus an image onto the retina | https://openstax.org/books/college-physics-2e/pages/26-glossary |
color constancy : a part of the visual perception system that allows people to perceive color in a variety of conditions and to see some consistency in the color | https://openstax.org/books/college-physics-2e/pages/26-glossary |
compound microscope : a microscope constructed from two convex lenses, the first serving as the ocular lens(close to the eye) and the second serving as the objective lens | https://openstax.org/books/college-physics-2e/pages/26-glossary |
eyepiece : the lens or combination of lenses in an optical instrument nearest to the eye of the observer | https://openstax.org/books/college-physics-2e/pages/26-glossary |
far point : the object point imaged by the eye onto the retina in an unaccommodated eye | https://openstax.org/books/college-physics-2e/pages/26-glossary |
farsightedness : another term for hyperopia, the condition of an eye where incoming rays of light reach the retina before they converge into a focused image | https://openstax.org/books/college-physics-2e/pages/26-glossary |
hues : identity of a color as it relates specifically to the spectrum | https://openstax.org/books/college-physics-2e/pages/26-glossary |
hyperopia : the condition of an eye where incoming rays of light reach the retina before they converge into a focused image | https://openstax.org/books/college-physics-2e/pages/26-glossary |
laser vision correction : a medical procedure used to correct astigmatism and eyesight deficiencies such as myopia and hyperopia | https://openstax.org/books/college-physics-2e/pages/26-glossary |
myopia : a visual defect in which distant objects appear blurred because their images are focused in front of the retina rather than being focused on the retina | https://openstax.org/books/college-physics-2e/pages/26-glossary |
near point : the point nearest the eye at which an object is accurately focused on the retina at full accommodation | https://openstax.org/books/college-physics-2e/pages/26-glossary |
nearsightedness : another term for myopia, a visual defect in which distant objects appear blurred because their images are focused in front of the retina rather than being focused on the retina | https://openstax.org/books/college-physics-2e/pages/26-glossary |
numerical aperture : a number or measure that expresses the ability of a lens to resolve fine detail in an object being observed. Derived by mathematical formulaNA=nsinα,NA=nsinα,wherennis the refractive index of the medium between the lens and the specimen andα=θ/2α=θ/2 | https://openstax.org/books/college-physics-2e/pages/26-glossary |
objective lens : the lens nearest to the object being examined | https://openstax.org/books/college-physics-2e/pages/26-glossary |
presbyopia : a condition in which the lens of the eye becomes progressively unable to focus on objects close to the viewer | https://openstax.org/books/college-physics-2e/pages/26-glossary |
retinex : a theory proposed to explain color and brightness perception and constancies; is a combination of the words retina and cortex, which are the two areas responsible for the processing of visual information | https://openstax.org/books/college-physics-2e/pages/26-glossary |
retinex theory of color vision : the ability to perceive color in an ambient-colored environment | https://openstax.org/books/college-physics-2e/pages/26-glossary |
rods and cones : two types of photoreceptors in the human retina; rods are responsible for vision at low light levels, while cones are active at higher light levels | https://openstax.org/books/college-physics-2e/pages/26-glossary |
simplified theory of color vision : a theory that states that there are three primary colors, which correspond to the three types of cones | https://openstax.org/books/college-physics-2e/pages/26-glossary |
Image formation by the eye is adequately described by the thin lens equations:P=1do+1diandhiho=âdido=m.P=1do+1diandhiho=âdido=m. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
The eye produces a real image on the retina by adjusting its focal length and power in a process called accommodation. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
For close vision, the eye is fully accommodated and has its greatest power, whereas for distant vision, it is totally relaxed and has its smallest power. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
The loss of the ability to accommodate with age is called presbyopia, which is corrected by the use of a converging lens to add power for close vision. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
Nearsightedness, or myopia, is the inability to see distant objects and is corrected with a diverging lens to reduce power. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
Farsightedness, or hyperopia, is the inability to see close objects and is corrected with a converging lens to increase power. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
In myopia and hyperopia, the corrective lenses produce images at a distance that the person can see clearlyâthe far point and near point, respectively. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
The eye has four types of light receptorsârods and three types of color-sensitive cones. | https://openstax.org/books/college-physics-2e/pages/26-section-summary |
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