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Ray model of light (Temperance), The Sun is main source of light - Coggle…
Ray model of light (Temperance)
Types of light interactions
Reflection
Bouncing off of light rays by objects when the light rays hit on them.
Transmission
Light travels through a medium without being absorbed or scattered.
Absorption
When an object does not reflect or transmit the light.
Reflection of light
Normal
A line drawn at a right angle to the mirror's surface where the incident ray strikes.
Incident ray
A light ray that strikes a surface.
Reflected ray
A light ray that leaves a surface.
Angle of incident (i)
The angle between the incident ray and the normal.
Angle of reflection (r)
The angle between the reflected ray and the normal.
The incident ray, reflected ray, and normal at the point of incidence lie on the same plane.
Laws of reflection
The angle of incidence (i) is equal to the angle of reflection (r).
Types of reflection
Diffuse reflection
Rays are reflected in many directions by uneven surface
An observer cannot see reflection clearly because not all of the reflected light rays is directed towards his eyes.
Regular reflection
Light rays are reflected by a smooth surface in a regular manner at the same angle and the rays are parallel to one another.
Beam of light
Divergent beam
Spreads out from light source
Convergent beam
Rays move towards a focal point
Parallel beam
Rays are parallel to each other
Image formed by a plane mirror
Plane mirrors have a smooth and flat surface.
They reflect light when light rays strike on them.
Virtual
Cannot be captured on a screen
No light rays actually hit the image
2.Upright
The object and its image has the same orientation of right-side up.
3.Laterally inverted
The left-hand side of the object appears to be the right-hand side of the image and vice versa.
4.Same size as object
Object and image have the same dimensions
5.Distance of object and image is equal
The image is as far behind the mirror as the object is in front of the mirror.
Construction of plane mirror
From an object, measure distance of the object from the plane mirror.
Use distance to find the location of the image from the plane mirror.
2.From an object, draw the light rays from the image travelling into the eye
Use the dotted lines to represent ‘virtual’ rays from the image.
From the reflected rays in front of the plane mirror, draw the incident rays from the object to their respective reflected rays.
Convex mirrors have wider field of view
Field of view
Area that can be viewed in the mirror
Mirrors in life
Plane mirror
Flat and smooth
Rear mirrors in vehicles
Help drivers see behind
At home
Decoration
Periscope
See objects from behind an obstruction
Convex mirror
Spread light rays out
Blind corner mirror
Help see objects around a bend
SIDE mirrors in vehicles
Provide a wider view of the road
Surveillence mirrors
Wider view of activities in shop
Concave mirror
Focus the light rays at a point in front of the mirror
Microscope
Magnify size of objects which are too small to be seen by eyes.
Cosmetic mirror
Provide a magnified facial image
Dentist's mirror
Provide magnified images of teeth
Refraction of light
Light can be transmitted easily through a transparent medium.
Air, glass and water are transparent.
Different transparent media have different optical densities.
Optical density: measure of how well a substance transmits light.
The higher optical densityt=light travels slower
When a light ray is transmitted in two media of different optical densities
refraction of light occurs.
Normal
Line drawn at 90° to the surface of a medium where the incident ray hits
Incident ray
Light ray which strikes a surface.
Refracted ray
Light ray which undergoes a change in speed.
Angle of incidence (i)
Angle between the incident ray and the normal.
Angle of refraction (r)
Angle between the refracted ray and the normal.
Bending of light rays when they pass from one medium into another medium with different optical density.
Less dense->more dense
Bending to normal
speed of the light ray in the optical denser medium is slower
more dense ->less dense
bends away from normal
speed of light in the less optical dense medium is faster
At 90° to another medium
No bending of light
Phenomena due to refraction of light
gives us a false impression of appearance or depth
These false impressions are caused by the refraction of light in the media with different optical densities.
Pencil appears to be broken in water
Colour
White light = 7 colour components
Components can be split by glass prism
light components travel with different speeds in the glass prism
so they are refracted at different angles
spectrum of colours can be dispersed and recombined by using two glass prisms.
The vertices and bases of these two glass prisms are arranged in the opposite directions.
Dispersion of light
Primary and secondary colours
Primary colours
Mix to make white light
Secondary colours
Combination of 2 primary colurs
Seeing coloured objects
White light strikes an object, some components of white light will be absorbed and others will be reflected by the object.
Give rise to the colour of the object
Coloured filter
A coloured filter is made of plastic or glass.
1 more item...
The natural or artificial dyes and pigments can make an object to appear a specific colour.
Reflecting colour components of light while absorbing the others.
Complementary colours
Colours that can be combined to make white light
Eg. Blue+yellow
Yellow has red and green
The Sun is main source of light
Light from light source travels in straight line
Light rays are emitted from light source and travel away from it
In all directions
Properties of light
A form of energy
Travels in a straight line
When it hits a surface
Can be reflected or refracted
Speed of light
3x10^8 m/s in a vaccum
