A
Acceleration:The rate of change of velocity
Ammeter:Used to measure current - to get a proper reading when measure current in an ammeter, the ammeter must be connected in series with the circuit.
Amplitude:The distance from the rest position on a wave to the point farthest out of the medium.
Angle of Deviation:The angle between the emergent ray and the incident ray. - the factors which affect the way a lens refracts light are the 1.) radii of curvature, and 2.) The center of curvature of the lens.
Angle of Incidence:The angle of the incident ray (the light ray approaching) to the normal.
Angle of Reflection:The angle between the reflected ray and the normal.
Angle of Refraction:The angle between the normal and the refracted ray (reflected)
Atoms:The elementary particles in the universe that make up all matter. They consist of protons (+) and neutrons (neutral) charges in its nucleus, and orbitting eletrons(-)
B
Batteries: Two or more cells in series. Primary batteries are those which can only used once, where as secondary cells are those which can be used again by recharging the battery.
Beam:A bundle of light rays.
Beats:Produced when two or more sound sources are placed beside one another and they interfere with each other to produce a beat. (one complete oscillation of from loud to soft and back to loud.) Or the difference between the two frequencies.
C
Converging Beam: One which the light rays come together.
Crest:The top part of the sound wave , and a trough is the bottom part. (in a transverse wave)
Cell:A source or power and voltage to a electron(s).
D
Diffuse Reflection:When light reflects in many different directions, after all the incident rays are parallel, or irregular reflection.
Displacement:The vector quantity of distance. It is known as the shortest distance along a single line from the beginning to the end.
E
Ear:Where we hear all of our sounds. It works with a very complex mechanism(s). A short description of how the ear works is as follows: The sound travels inlongitudinal waves, thus these waves hit the typanic membrane (eardrum) and cause pressure variances in the ear. these pressure variances travel through the hammer, then to the anvil and finally to the stirrup, which is attached to the oval window. These act as a interlocking mechanism, which allows sound to be heard. Since the oval window is 1/20th the area of the eardrum, sound is multiplied by a factor of 20. These lead to a end magnification of 40 x. The cochlea has small hairs inside of it vibrating at their natural frequencies when the sound enters this part of the ear. 23 000 of these small hairs send nerve impulses to the brain, where it is processed into a sound.
ECHO Calculations:Also, when dropping something (e.g.) down a well, the time taken for the sound to be heard is the time taken to fall (where v1=0, a = 9.8 m/s2), and the time for an echo to come back up. The temperature for this type of question is essential.
Electromagnetic Spectrum (EMS):The continuous spectrum of light in the following order from highest frequency to lowest frequency: Gamma rays X-rays UV rays Visible light Infrared light Microwaves Radio waves - The electromagnetic spectrum is said to be continuous, as it is thorough from beginning to end. there are no holes. The various "bands" of light do not change directly, they instead gradually fade into the different type of light.
Earth Bound Telescopes: have a size barrier. This is, as a telescope approaches 200", the mirror becomes warped or not curved in some sections. Also, telescopes on Earth can only be used on clear days, and the atmosphere absorbs light from the sky, making it hard to see far away object. To solve this problem, telescopes can be placed in space (Hubble), made with small individual sections, or with a new material. (such as mercury spun in a wheel to give it a parabolic shape.)
F
Focal Length (f)The distance from the centre of the mirror to the F. This is 1/2 the distance of the radius.
G
Gallilean Telescope: A telescope which is not as effective as the previous ones. It's structure has the light entering a converging lens, and then the image is made right side up by a diverging lens. This is a ineffective telescope, as the light gets dimmed, and the images become more dimmer.
Gravity: The force exerted by the Earth to hold us down. There is a equal but opposite force to gravity. called normal force. This normal force is perpendicular to the surface it is in contact with. The force of gravity exerted by the Earth on an object can be calculated by multiplying the mass of the object, by the acceleration due to gravity factor - 9.8 m/s2. Thus the formula becomes F = mg.
H
I
J
K
Keplerian Telescope: is one which is formed with the aid of 2 converging lenses. They arranged in such a way, that the focus of the first lens is placed just inside the focus of the second This allows the image to be virtual and magnified.
Kinetic Energy: The energy an object has due to it's motion. Such an example is the energy a car posses when it is moving.
L
Lens:Allows light to pass through it rather then reflect on it like a mirror.
Light:A form of radiant energy that has a speed of 3.0 x 10^8 m/s
Longitudinal Wave: A wave which is parallel to the medium (sound)
Loop:When waves hit a fixed end, they return back to the source on the other side of the medium. In the formation of this standing wave, a loop is formed. The loop is 1/2 the wavelength , this is the length of a crest or trough
Loudness of a SoundDetermined by the amplitude of the wave. Thus the larger the amplitude, the more noise it makes.
Luminous:A object is said to have produced it's own light, where as a non-luminous object is one that gets it's light from another object (moon)
M
N
Node: A point on the wave which remains still, or has no vibration
Nodal lines:Resulted when 2 speaker are placed beside each other in phase. This results in a nodal line or silent point where the compressions superimpose the rarefactions to give a sound of 0. Similarly, where the rarefaction's, and compressions meet their same, they become louder. This lines are called antinodal lines.
Normal:A line constructed perpendicular to the surface
O
Octave:Is when two notes have a ratio of their frequencies of 2:1. Thus the note with a frequency of 512 Hz, is 1 octave higher then a note with a frequency of 256 Hz. ** A note that has overtones does not sound as pure as a note without overtones. ** As a wave gets more and more overtones, it is said to have greater wave complexity.
Opaque:Substances that allow no light through them. (eg: wood)
P
Phase:When something is in phase with another wave, it is said to be moving in the same direction and same wavelength, frequency, pitch etc. with the other wave.
Pitch:Determined by the frequency of the wave.
Potential EnergyThe energy as a result of gravity or a form of acceleration(answer in Joules (J)
Principle Focus (F):The point where the light rays converge, or appear to diverge from
Pure Note:A note which has no overtones, and is in its natural frequency.
Q
R
Radii of curvature:The distance from the centre of the mirror to the edge of the mirror.
Rarefaction: The part of a longitudinal wave which is stretched out, where as a compression is the part which is pushed together. (longitudinal wave)
Resonance: When a medium is vibrating at the same fundamental frequency of another object. (e.g. - when the wind was resonating at the natural frequency of the Tacoma bridge, it started to "shake rattle and roll", as the amplitude of the bridge continually increased and decreased.
Rich note: A note with many overtones.
S
Sound: A longitudinal wave, and can be pushed in all directions. It needs a medium to move, as without one it produces no noise. Thus, sound cannot be heard in space.
SONAR: It must be noted, that when a sound takes 10 s to come back to you when using SONAR, the time taken is actually 5.0 s for one way. Thus when asked to find the depth of a ocean, etc. the time taken which must be used is that of one way.
Specular Reflection: When parallel light rays reflect back in parallel light rays (flat mirror)
Speed of Sound The speed of sound in still air at 0 degrees Celsius is 331 m/s. It depends on 2 main factors, temperature, and the material. The speed of sound in air can be calculated by taking in to consideration the temperature.
Spherical Aberration:Occurs when the converging rays in a concave mirror are not properly focused in one area. To avoid this, parabolic mirrors are used, as they do not have spherical aberration.
Standing Wave Pattern:A pattern resulted by a wave train. It appears that the wave is not moving, but actually is, as it is moving too fast for the eye to see.
Super Trough & Super crest: Are resulted when the either two crests come together to make a super crest, or two troughs come together to make a super trough. - the human ear can detect frequencies between the frequencies of 16Hz - 20 000 Hz - Frequencies above this benchmark are called ultrasonic frequencies. - As a person ages, the ears do not function as well, thus there hearing abilities diminish somewhat over the years.
Supersonic Speeds: When something goes faster then the speed of sound it is said to be going at supersonic speeds. (speeds greater then the speed of sound) ** A object moving faster then the speed of sound gives off sonic booms. This is the sound produced by the continual spillage of air around the object. (usually heard when planes pass over head.)
T
Transparent: When a material allows most of the light beams hitting to travel through. (eg: clear glass)
Translucent: When a material allows some of the light beams hitting it to pass through (eg: frosted glass)
Transverse Wave: When the direction of the wave is perpendicular to the medium. (light)
Terrestrial Telescope: Uses the same idea in mind as the Keplerian telescope, except it is used to produce a image that is right-side up, as it's purpose is one which can be used on Earth. The addition to the terrestrial telescope is that a field lens is added between the objective lens and the eyepiece. It inverts the first real image, which allows the final image to be right-side up.
U
V
Vector: The quantity which can be described by using a number, unit and a direction, (e.g.) Displacement, velocity, force, etc
Vector Diagram: Used to display the vector quantities, etc. The tail to tip method is used to solve various aspects of non-collinear vectors. (e.g.) John walked 5 km[N 30 W] then walked 10 km [E]. Find his displacement.
Velocity:The displacement per unit time. In a velocity vs. time graph, the acceleration can be taken by taking the slope. The velocity from an acceleration vs. time graph can be taken by taking the area beneath the graph.
Vertex:The geometrical centre of the mirror
W
Wave:A disturbance in a material as a result of energy. There are two main types of waves: longitudinal and transvrerse. Light is a transverse wave, whereas sound is a longitudinal wave.
Wave Train:A continual push of waves.
WavelengthThe length of a complete wave. In a transverse wave, this is the length of a crest and trough.
X
Y
Z