P14 Flashcards
how is virtual image formed
where rays of light appear to have come from and cannot be seen on screen
what is specular reflection
reflection from a smooth surface such as a mirror
what is diffuse reflection
reflection from a rough surface
what happens when a light ray travels from a less dense medium to a more dense medium such as air to glass
it is refracted towards the normal
what happens when a light ray travels from a more dense medium to a less dense medium such as glass to air
light is refracted away from the normal
where do the wavelengths of the visible spectrum increase from
increase from violet to red
what does the human eye see
different frequencies of light as different colours
the frequencies form a continuous spectrum so one colour merges into another
what do colour filters do
absorb certain wavelengths and reflect others
what do pigments in a material do
absorb light of specific wavelengths and strongly reflect others
what does a white surface do
has no pigments so reflects any wavelength
what do transparent objects do
transmit all the light incident on them
what do translucent objects do
allow light to pass through but is scattered or refracted
what do opaque objects do
absorb all the light incident on them
what do parallel rays of light do when they pass through a convex lens
are refracted so they converge to a point
what is the point called where the rays meet
principle focus
what is the distance from the centre of the lens to the principle focus called
focal length
what happens if the object is further away from the lens than the principle focus
an inverted real image is formed that is smaller than the object
wha =t happens if the object is nearer to the lens than the principle focus
an upright, virtual image is formed behind the object
the image is magnified
what happens when parallel rays pass through a concave lens
they are refracted so that they diverge away from a point
the point is called a principle focus
what is the image produced by a diverging lens
always virtual
