Cheatography

# Science 10: Unit II - Physics Cheat Sheet by ashireii

long examination 2nd qtr

### WAVES

 - distur­bances that travel through a medium or a vacuum in space resulting in vibrations - the energy passing through a medium or a vacuum creates the waves

### Mech­anical Waves

 - waves that requires a medium or any matter for it's energy to travel - the energy and vibrations of these waves interact with the molecules of a medium that can come in the forms of solid, liquid, and gaseous - sound waves, water waves, seismic waves and slinky or spring waves are some examples of this type of wave

### Elec­tro­mag­netic Waves

 - can travel through both matter and vacuum - formed through the intera­ction of electric fields and magnetic fields - radio waves and microwaves are examples of this wave

### Oscill­ations

 - continuous back-a­nd-­forth or side-t­o-side movements of an object - waves can produce an oscill­ation in the particles of the medium through which it travels

### Transverse Waves

 - particles are oscill­ating towards a direction perpen­dicular to the direction of the wave - must travel through a relatively solid medium because it cannot pass through liquid or gaseous matter - consists of individual waves that oscillates in an altern­ating upward and downward motion

### Longit­udinal Waves

 - can travel through a solid, liquid or gaseous medium

### Charac­ter­istics of a Wave

 Crest - the peak or highest point of the upward moving wave Trough - the lowest point at each valley Normal Line - the imaginary horizontal line in the middle of the wave Amplitude - the distance between the normal line and the tip of the crest or trough Wavelength ( λ ) - the distance between two crests or two trough Phase - two wave points that are travelling with the same speed, displa­cement and height towards the same direction Period - refers to the time that one crest or trough completes one cycle or travels a distance of one wavelength Frequency ( f ) - the number of full wavele­ngths travelling through a point in space per unit time the shorter the wavelength, the higher the frequency and vice versa

### Speed of Wave

 v = λf velocity = wavelength x frequency wavelength = velocity / frequency frequency = velocity / wavelength

### Properties of Mechanical Waves

 Reflection - the wave's frequency and wavelength are simply mirrored or reflected by the returning wave Refraction - a wave travelling in one medium encounters another wave and bends at a different angle Diffra­ction - wave passes through the open spaces or travels around the edges of the barrier , the diffracted wave disperses outwards and arches as it travels Interf­erence - two waves meet along the same medium Constr­uctive Interf­erence - combin­ation of two interf­ering waves moving towards the same direction Destru­ctive Interf­erence - waves are combined and decreases each others' amplitude

### ELEC­TRO­MAG­NETIC WAVES

 - EM WAVES - they propagate along two oscill­ating fields that lie perpen­dicular to each other - oscill­ating electric fields - oscill­ating magnetic fields - travels at the same speed of 3 x 108 m/s in a vacuum Light Waves - most accessible EM wave

### Electr­oma­gnetic Spectrum

 - classi­fic­ation of electr­oma­gnetic waves according to their freque­ncies and wavele­ngths

### Seven Regions of Electr­oma­gnetic Spectrum

 Radio Waves - longest wavele­ngths, the least amount of energy, 1cm to 1km, 3kHz to 300gHz Microwaves - freque­ncies of radio waves and microwaves overlap, highest frequency for radio waves is lowest for microw­aves, 1mm to 1m, 300mHz to 300gHz Extremely High Frequency ( EHF ) - 30gHz to 300gHz, 10mm to 1cm, for radio astronomy Super High Frequency ( SHF ) - 3gHz to 30gHz, 1cm to 10cm, for microwave ovens Ultra High Frequency ( UHF ) - 300mHz to 3gHz, 1dm to 1m, for satellite commun­ica­tions Infrared Rays - all objects near room temper­ature are capable of emitting infrared radiation, 0.74mcm to 1mm, 300gHz to 400tHz Far-in­frared rays - 300gHz to 30tHz Mid-in­frared rays - 30m to 120m Near-i­nfrared rays - 120tHz to 400 tHz Visible Light - allows human eyes to see things around, 300nm to 700nm, 400tHz to 790tHz Ultrav­iolet Light - known as black lights that are used in detecting skin diseases, 10nm to 40nm, frequency higher than visible light X-rays - used to examine the condition of human bones, 0.01nm to 10nm, 30pHz to 30eHz Hard X-rays - penetr­ating numerous solid matter, energy >10KeV Soft X-rays - energy used in producing images of micros­copic objects Gamma Rays - similar charac­ter­istics as X-rays, <10pcm, greatest energy 50KeV to 50GeV

### REFLECTION OF LIGHT ON MIRRORS 1

 Reflection - when light rays is emitted by a particular source that interacts with a medium that serves as a barrier which the ray of light bounces back Specular Reflection - when light hits a smooth, flat surface and reflects an image almost identical to the object Diffused Reflection - when light hits a rough, uneven surface and the reflected light rays scatter in different directions Law of Reflection - the ray of light approa­ching the mirror is called incident ray (IR), while the bounces ray from the mirror is called reflected ray (RR). at the point where the IR meets the surface of the mirror a hypoth­etical vertical line, perpen­dicular to the surface between the two rays is called normal divides the angle formed by the IR and RR. the angle of incidence (θi) refers to the angle formed by the incident ray and the normal, while the angle of reflection (θr) refers to the angle formed by the reflected ray and the normal. when light hits a barrier, the angle of incidence is equal to the angle of reflection [ θi = θr ] Plane Mirrors - made up of flat, reflective surfaces that produce a reflection that is similar to the object line of sight - the process of directing your sight towards a certain point in space lateral inversion - "mirroring" the reflection is reversed forwards and backwards because the object and the mirror is facing each other virtual image - forms when the light rays bouncing from an illumi­nated object appear to be meeting or converging with each other at a definite point but not actually meet Curved Mirrors - cresce­nt-­shaped mirror that is a part of a reflective sphere Concave Mirrors - reflective surface that curves inwards [ real image ] Convex Mirrors - reflective surface that bulges outwards [ virtual image ]

### REFLECTION OF LIGHT ON MIRRORS 2

 center of curvature - center of the curvature and the center of the sphere itself principal axis - line in the middle that intersect points and divides the sphere into two hemisp­heres vertex - where the axis meets the edge of the sphere or the surface of the curved mirror focal point - marks the midpoint between the center of the curvature and the vertex focal length - the distance between the focal point and the mirror's vertex [one half the radius of the curvature radius of curvature - marking the distance between the vertex and the center of the curvature Ray Diagram Method - determines the location of images formed in curved mirrors by tracing the path of light rays passing through an object and bouncing on the surface of a mirror

### OPTICAL INSTRU­MENTS

 human eyes - windows which light enters and enables humans to see, an inch in diameter cornea - clear protective outer layer of the eye sclera - white part of the eye retina - nervous tissue composed of millions of nerve cells farsig­hte­dness / hyperopia - distant objects are much clear than nearby objects nearsi­ght­edness / myopia - nearby objects are much clear than distant objects astigm­atism - causes blurred vision due to an irregu­lar­-shaped cornea microscope - optical instrument for magnifying the tiniest elements eyepiece lens - makes up the top of the microscope objective lenses - magnify the view of the specimen focusing mechanisms - two to four objective lenses with varying magnif­ication power telescope - for viewing enormous but distant celestial objects refracting telescope - use lenses to collect weak light from heavenly objects and magnify the image reflecting telescope - use of mirrors that bend parallel light rays and make them converge into a focus Newtonian reflector - flat mirror that directs the reflected rays to an eyepiece Cassegrain reflector - primary mirror with a hole in the middle and convex secondary mirror Coude telescope - secondary convex mirror and an angled mirror binoculars - has two small side by side telescopes camera obscura - closed box with a tiny hole, light passes and projects inverted image daguer­reotype camera - smaller box with an ocular tube in the middle, polished silver­-coated plate, light sensitive surface film camera - late 19th to early 21st century, used convex lens and film strips digital camera - advanced photog­raphy, 21st century, convex lens, sensor that collects pixels Largest Telescopes - Hubble Space Telescope, Extremely Large Telescope