Physics Flashcards
What is a medium
any physical substance through which energy can be transferred
What is radiation?
A method of energy transfer that does not require a medium; the energy travels at the speed of light
What is electromagnetic waves?
A wave that has high electric and magnetic parts, does not require a medium, and travels at the speed of light
What is visible light?
Electromagnetic waves that the human eye can detect
What is the electromagnetic spectrum?
The classification of electromagnetic waves by energy
What is visible spectrum?
The continuous sequence of colours that make up white light
What does luminous mean?
Produces its own light
What does non luminous mean?
Does not produce it’s own light
What is incandescence?
The production of light as a result of high temperatures
What is electric discharge
The process of producing light by passing an electric current through a gas
What is phosphorescence?
The process of producing light by the absorption of Ulithi violet light over an extended period of time
What is fluorescence?
The immediate emissions of visible light as a result of the absorption of ultraviolet light
What is chemiluminescence?
The direct production of light as the result of a chemical reaction which little or no heat produced
What is bioluminescence?
The production of light in living organisms as the result of a chemical reaction with little or no heat produced
What is triboluminescence?
The production is light from friction as a result of scratching crushing or rubbing certain crystals
What is a light-emitting diode (LED)?
Light produced as a result of an electric current flowing in semi conductors
What is a semiconductor?
A material that allows an electric current to flow in only one direction
What is a light ray?
A line on a diagram representing the direction and path that light is travelling
What are geometric optics?
The use of light rays to determine how light behaves when it strikes an object
What is an incident light?
Light emitted from a source that strikes an object
What is transparent?
When a material transmits all or almost all incident light; objects can be clearly seen through the material
What is translucent?
When a material transmits some incident light but absorbs or reflects the rest; objects are not clearly seen through the material
What is opaque?
When a material does not transmit any incident light; all incident light is either absorbed or reflected; objects behind the material can not be seen at all
What does image mean?
Reproduction of an object through the use of light
What is a mirror?
Any polished surface reflecting an image
What is a reflection?
The bouncing back of light from a surface
What is a plane mean?
Flat
What is an incident ray?
The incoming ray that bounces off a reflective surface
What is a normal?
The perpendicular line to a mirror surface
What does perpendicular mean?
At right angles
What is an angle of incidence?
The angle between the incidence ray and the normal
What is the angle of reflection?
The angle between the reflected ray and the normal
What is specular reflection?
Reflection of light off a smooth surface
What is a virtual image?
An image formed by light coming from an apparent light source; light is not arriving at or coming from the actual image location
What is lateral inversion?
The orientation of an image in a plane mirror that is backwards and in reverse order
What is a concave (converging) mirror?
A mirror shaped like part of the surface of a sphere In which the inner surface is reflective
What is a convex (diverging) mirror?
A mirror shaped like part of the surface of a sphere in which the outer surface is reflective
What is the centre of curvature?
The centre of the sphere whose surface has been used to make the mirror
What is a principal axis?
The line through the centre of curvature to the midpoint of the mirror
What is the vertex?
The point where the principal axis meets the mirror
What does it mean to converge?
To meet at a common point
What is the focus?
The point at which light rays parallel to the principal axis converge when they are reflected off a concave mirror
What is a real image?
An image that can be seen on a screen as a result of light rays actually arriving at the image location
What does diverge mean?
To spread apart
What is refraction?
The bending or change in direction of light when it travels from one medium to another
What is an angle of refraction?
The angle between the refracted ray and the normal
What is the index of refraction?
The ratio of the speed of light in a vacuum and the speed of light in a medium, n=c/v; this value is also equal to the ratio of the sine of the angle of incidence in a vacuum to the sine of the refracted ray in a medium, n=sin<i></i>
What is a critical angle?
The angle of incidence that results in an angle of refraction of 90 degrees
What is the total internal reflection?
The situation when the angle of incidence is greater than the critical angle
What is a retro-reflector?
An optical device in which the emergent ray is parellel to the incident ray
What is apparent depth?
The depth that an object appears to be at due to the refraction of light in a transparent medium
What is a mirage?
A virtual image that forms as a result of refraction and total internal reflection in earths atmosphere
What is dispersion?
The separation of white light into its constituent colours
What is a converging lens?
A lens that is thickest in the middle and that causes incident parallel light rays to converge through a single point after refraction
What is a diverging lens?
A lens that is thinnest in the middle and that causes incident parallel light rays to spread apart after refraction
What is the optical centre?
The point at the exact centre of the lens
What is the principal focus
The point on the principal axis of a lens where light rays parallel to the principal axis converge after refraction
What is an emergent ray?
The light ray that leaves a lens after refraction
What is the thin lens equation?
1/f = 1/do + 1/di
What is the magnification equation?
M = hi/ho + di/do
What is accommodation?
The changing of shape of the eye lens by eye muscles to allow a sharply focused image to form on the retina
What is hyperopia?
The inability of the eye to focus light from near objects; farsightedness
What is positive meniscus?
A modified form of the converging lens shape
What is presbyopia?
A form of farsightedness caused by a loss of accommodation as a person ages
What is myopia?
The inability of the eye to focus light from distant objects; nearsightedness
What is a negative meniscus?
a modified form of the diverging lens shape
What speed does light travel in a vacuum?
3.00 x 10^8 m/s
What speed does light travel in water?
2.26 x 10^8 m/s
What speed does light travel in acrylic?
1.76 x 10^8 m/s
Light bends ______ the normal when the speed of light in the second medium is less than the speed of light in the first medium.
Toward
Light bends ______ from the normal when the speed of light in the second medium is greater
Away
What is snells law?
N= sinOi/sinOr
What is the critical angle of a diamond?
24 degrees
What are the 5 phenomenas related to refraction?
Apparent depth, flattened sun, mirage, shimmering and the rainbow.
