Light Flashcards
What happens when rays hit a plane mirror?
They are reflected
What are the characteristics of an image formed by a plane mirror
- same size as the object
- inverted
- virtual
When light is reflected how do angle i and r compare?
angle of incidence=angle of reflection
How are the angles of incidence and reflection measured
relative to the normal
What is a virtual image?
An image produced on the same side of the lens as the object and that cannot be projected
What is a virtual image
An image produced on the opposite side of the lens
and that can be projected
What kind of image is produced by a plane mirror
A virtual image
What is refraction?
Refraction is the change in speed, of a wave crossing a boundary between two media, resulting in change of direction
What property of a wave is not changed by refraction?
The frequency
What is the critical angle?
The angle of incidence which produces an angle of refraction at 90°
What is internal reflection ?
When light reaches aboundary and it reflectd back into the medium it came from
What is total internal refraction ?
When a ray of light is fully reflected into the medium it came from, when reaching boundary between media.
When does total internal refkection happen?
When the angle of incidence is greater than the critical angle
Define refractive index
The ration of the speed of light in a vacuum compared to the speed of light in any medium.
Give the equation for the refractive index
refractive index= sin(i)/sin(r)
refractive index=1/sin(i)
When light passes through a converging lens ____
The light rays bend towrads the normal, and meet at a focal point
What is the principla focus of a lens ?
A focal point before the convex lens, from which the light rays seem to appear from, or the focal point after concave lens where all the rays meet
How can lenses act as magnifying glasses?
By producing an enlarged, virtual image
How does wavelenght affect refraction?
Shorter wavelenght - waves refract more
What happens when a white light is shone through a prism
It seperates into a spectrim of all its coloured light components
Why is white light seperated by a prism
Each differnt coloured light wave has a different wavelength. The greater the wavelength, the slower the speed in glass and the greater the refractive index
List, in the correct order, the colour
spectrum produced by the dispersion of
white light
red, orange, yellow, green, blue, indigo, violet
What is monochromatic light?
Light of a single frequency
