Physics Vocabulary:Term I
prefixes for metric system
deci = one tenth centi= one hundredth milli = one thousandth Kilo= thousand Yotta= 10^24 (10 to the 24 power)
Gamma Waves
gamma wave is a pattern of neural oscillation in humans with a frequency between 25 to 100 Hz, They have a high frequency and a very short wavelengths also form of X-Ray
(Total Internal Reflection)
the complete reflection that takes place within a substance when the angle of incidence of light striking the surface boundary is less than the critical angle
yotta
10 to the 24th power 1 000 000 000 000 000 000 000 000
Transverse Wave
A wave with vibration at right angles to the direction the wave is traveling
Incident Ray (Ray of Incidence)
The Ray of light that travels from the object to the reflecting surface
laser
A concentrated beam of light with only one wavelength
Penumbra
A partial shadow that appears where light from part of the source is blocked and light from another source is not blocked
Longitudinal Wave
A wave in which the vibration is in the same direction as that in which the wave is traveling, rather than at right angles to it
Angle of Refraction
The angle between the ray of refraction and the normal
Constructive Interference
Addition of two or more waves when wave crests overlap to produce a resulting wave of increased amplitude
Angle of Reflection
Angle between a reflected ray and the normal to a surface
Angle of Incidence
Angle between an incident ray and the normal to a surface.
Destructive Interference
Combination of waves where the crests of one wave overlap the troughs of another wave resulting in a wave of decreased amplitude
Infrared Waves
Electromagnetic Waves of frequencies lower than red visible light are called infrared light
Period
In general the time it takes to complete a single cycle
Snell's Law
Index of Refraction (of substance) x Sin(angle of substance) = Index of Refraction (of another substance) x Sin(angle of another substance)
Reflected Ray (Ray of Reflection)
The Ray of light that is reflected form the reflected surface to the eyes
Micro Waves
Microwaves are electromagnetic waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz) and 300 GHz. Microwaves are very short radio waves that travel in an invisible circular motion through the air. Microwaves go faster than television waves but slower than infrared rays (microwaves travel at the speed of light, 186,282 miles per second!). They are stronger than radio frequency waves, but weaker than X-rays.
Radio Waves
Radio waves have the longest wavelengths in the electromagnetic spectrum but the slowest frequencies
Slinky
Slinky or "Lazy Spring" is a toy consisting of a helical spring that stretches and can bounce up and down.
Metric Prefix
Syllable or group of syllables attached to the beginning of a metric unit in order to make the unit larger or smaller.
Virtual Ray
The "ray" of light behind the mirror; there is no ray really there. It is the ray we draw to make sense of how things work
EM Spectrum Electromagnetic Spectrum
The Electromagnetic Spectrum is a continuous range of waves extending from radio waves to gamma waves. Waves are the same in nature but differ in frequency and wavelength
Diffraction
The bending of a wave around a barrier, such as an obstacle or the edges of an opening
Umbra
The darker side of a shadow where all the light is blocked
Amplitude
The distance from the midpoint to the maximum (crest) of a wave or equivalently from the midpoint to the minimum (trough)
Wavelength
The distance from the top of a crest of a wave to the top of the following crest, or equivalently, the distance between successive identical parts of a wave
Hypotenuse
The hypotenuse is the side opposite the right angle
Law of Reflection
The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection
Light Waves
The light we can see. The lowest frequency of light that we can see is red. The highest visible frequencies are nearly twice the frequency of red and appear violet
Frequency
The number of events( cycles, vibrations, oscillations, or any repeated event) per time; measured in hertz: Inverse of period
normal
The perpendicular line to the reflective or the refractive surface
Sine(angle)
The ratio of the length of the side opposite the angle over the length of the hypotenuse.
Refracted Ray (Ray of Refraction)
The ray of light that is refracted through a substance to the eyes
Wave Speed
The speed of a wave depends on the medium it travels through. Whatever the medium the speed, frequency, and wavelength of the wave are related: wave speed = wavelength x frequency The equation is: Speed = wavelength x frequency (v=λf)
The Index of Refraction
The velocity at which light moves in a substance compared to air in any given substance. Th higher the number the denser the substance
reflection from free end
This is reflection against a medium that is free to move. Note that in this case, the pulse is NOT inverted.
reflection from fixed end
This is reflection from an obstacle. The pulse is inverted.
Laser Slit experiment ( or Double Slit experiment
Thomas Young"s double slit experiment was extremely important in wave theory and proved light traveled in waves
Ultraviolet waves
Type of X-Rays that have high frequency and short wavelengths
Metric System
a decimal system of weights and measures based on the meter and the kilogram and the second. This system was originally established in France in the 1790s
Light Ray
a line of light
Pythagorean Theorem
a²+b²=c² The Pythagorean Theorem stated algebraically is: for a right triangle with sides of lengths a, b, and c, where c is the length of the hypotenuse.
centi
hundredth
Medium
the material through which a wave travels
Adjacent
the side of a right triangle that touches the current angle that isn't the hypotenuse
Opposite
the side opposite the current angle
object
the thing that is reflected in the mirror
image
the virtual object
Kilo
thousand
milli
thousandth
Lifeguard Metaphor
when light refracts it takes the fastest route not the shortest route