P14 Light Flashcards
The angle of incidence=
The angle of reflection
The normal is the ___?
theoretical line perpendicular to the mirror
What is specular reflection?
Reflection in which light travelling towards a surface in one direction is all reflected in a single direction.
What is diffuse reflection?
Where light reflects off a rough surface and scatters at different angles.
What is refraction?
Process by which a wave changes speed and sometimes direction upon entering a denser or less dense medium, eg a light ray changes direction when refracted by a lens.
What happens to the direction of light when it passes from air to glass or from glass to air?
Glass is denser than air, so a light ray passing from air into glass slows down. If the ray meets the boundary at an angle to the normal, it bends towards the normal.
The reverse is also true. A light ray speeds up as it passes from glass into air, and bends away from the normal by the same angle.
The colours of objects depends on _____?
The pigment in it that absorbs and reflect specific wavelengths.
Does the wavelengths from red to violet of the visible light spectrum increase or decrease?
Increase
What do colour filters do?
Only let their specific colour/light wavelength be transmitted
e.g red filter lets only red light out
What are transparent materials?
A material, object or substance which allows light to pass through it so that an image can be clearly seen through it.
What are translucent objects?
A material, object or substance which allows some light to pass through it.
What are opaque objects?
A material, object or substance which does not allow light to pass through it. The light is absorbed, scattered or reflected– so it does not pass through the material.
What is a convex lens?
A convex lens is thicker in the middle than it is at the edges. Parallel light rays that enter the lens
converge. They come together at a point called the principal focus
What are concave lenses?
A concave lens is thinner in the middle than it is at the edges. This causes parallel rays to diverge. They separate but appear to come from a principle focus on the other side of the lens.
What are real images?
An image that is formed where the rays of light are focused.
