chapt 5 : ray model of light Flashcards
how does light travels
in a striaght line
what are luminous objects
objects that emit light on their own
what are non-luminous objects
objects that do not emit light on their own
how do we see non-luminous objects
when they are near a light source, they will reflect the light from the object and enters our eyes
how do we see luminous objects
light emitted by them enters our eyes
definition of reflection
when light is being bounced off a surface
what is a plane mirror
a mirror that has a flat and smooth surface
what are 3 characteristics of the plane mirror
the image is upright,
it is laterally inverted
and the image shown is the same size as the object.
what are 3 uses of plane mirror
check appearance
used in interior design to make the house look bigger
to reflect eye chart so that it appears further
types of curve mirror
convex and concave
what are 3 uses of convex mirror
blind spot mirror at the road junction
security mirrors
side or rear view mirror in the car
what is a convex mirror
a mirror that has a diminished image and provides a wider field of vision
what is the characteristic of the convex mirror
it buldges out
what are 5 uses of concave mirror
make-up mirror
dental mirror
torch light
headlight of car
microscope mirror
what is a concave mirror
a mirror that provides a bigger field of vision and a larger image
what is the characteristic of concave mirror
it buldges inwards
what happens when the reflecting surface is rough
most of the light is absorbed and most of the light will be reflected in a scattered manner. this is called diffuse reflection
what happens when the reflecting surface is smooth and flat
light will be reflected in one direction and this is called regular reflection.
what happens when light passes through different mediums
it will bend at the boundary due to the change in speed of light in the medium, this bending of light is known as refraction
what happens to the bending and the speed of light when it enters a denser medium
the light will bend towards the normal and the speed slows down.
what happens to the bending and the speed of light when it enters a less dense medium
the light will bend away from the normal and the speed increases.
what happens to the light when it enters a perpendicular medium
it will not bend
will the object in a dense medium appear to be closer or further
closer
what are the colours in the spectrum
red
orange
yellow
green
blue
indigo
violet
what are the uses of infrared radiation
tv remote control
cooking
motion detector
burglar alarm
thermal imaging cameras
what are the harmful effects of IR
temperature increase
damage to eye
what are the uses of UV
to sterilise medical equipments
disinfect drinking water
helps produce vitamin
sunbed for tanning
what are the harmful effects of UV
harms eye
causes skin cancer
uses of visible light
photosynthesis
enable us to see
harmful effects of visible light
causes chemical change in some materials
light pollution
blue light from electronic devices affects our sleep
affects an animal’s ability for carry out daily activities
