Physics Grade 10 Topic 1-5

Sources of light Light is a spectrum- meaning some light is visible There are countless sources of light, but they can all be categorized under either of the two following categories- Natural sources Objects that emit light for example the sun, moon, stars and some living organism by bioluminescence. Artificial sources Light can artificially be created under three BROAD categories Incandescent sources- when certain objects are heated to a high temperature they emit light. Both infrared and visible light is produced. Ex. Candle.  Luminescent sources- produced by accelerating charges in a luminescent material, bypassing current through the material. Ex. Electric Bulb.  Gas discharge sources-  when electricity passes through certain gases at low pressure. light is produced. Ex. Neon lamp. Frequency: Number of waves that pass in a certain period of time Wavelength:  Distance between two corresponding points on adjacent waves If the frequency is high, the wavelength is shorter. Whereas if  the wavelength is bigger, f is lower Speed of light is about 3.00 x 10^8m/s Other types of light emission:  Fluorescence- emission of light from a substance that has absorbed light Phosphorescence- energy absorbed by substances then released slowly, glow in the dark Chemiluminescence- light is the product of a chemical reaction, two high energy chemicals break down to release light    

Light and Reflection  Law of reflection The angle of incidence is equal to the angle of reflection The incident ray, the normal to the mirror at the point of incidence and the reflected ray, all lie in the same plane. Reflection-  the change in direction of light waves when it bounces off a surface Medium- substance through light travels Ray- straight line that shows how light travels and which direction indicated by arrows Incident ray- from light source/ object to surface/ mirror Normal- perpendicular line to the surface, shows where ray of light meets surface Reflected ray- begins where the point of incident ray and normal meet Angle of incidence- angle between incident ray and normal Angle of reflection- angle between reflected ray and normal Plane Mirror- mirror with a flat reflected surface Virtual image- image formed by rays that seems to be coming from a position but isn't, not real. 

Images in a Plane Mirror SOLT Size will always be the same Orientation will always be upright Location will be the same as they are the same distance away Type of image will always be inverted  

Images in Concave Mirrors SOLT Size depends could be bigger or smaller Orientation is generally inverted Location is either behind C, on C, between C and F, on F, or ahead of F Type of image is most likely real

Image in Convex Mirrors SOLT Size is smaller Orientation is upright Location is between vertex and focal point Type is always virtual