Light Flashcards
What type of waves are light waves?
light waves are transverse waves
What three things can light waves be?
reflected
refracted
diffracted
What allows us to see most objects?
reflection of visible light is what allows us to see most objects
light bounced off the objects into our eyes
What happens when light reflects from an uneven surface?
when light reflects from an uneven surface such as a peice of paper, the light reflects off at all different angles and you get a diffuse reflection
What happens when light reflects from an even surface?
when light reflects from an even surface (smooth and shiny like a mirror) then it’s all reflected at the same angle and you get a clear reflection
What is the law of reflection?
the angle of incidence = the angle of reflection
![](https://s3.amazonaws.com/brainscape-prod/system/cm/184/406/595/a_image_thumb.jpg?1459003263)
When are images formed?
images are formed when light waves cross
Always measure from the … to the ray itself
Always measure from the Normal to the ray itself
When is a real image produced?
a real image is produced when real rays of light cross
When are virtual images produced?
a virtual image is produced when virtual rays of light cross
What are the differences between a real image and a virtual image
a real image is produced when real rays of light cross and can be projected
a virtual image is produced when virtual rays of light cross and cannot be projected
What is three things is virtual image compared to the real image?
the virtual image is:
the same size
laterally inverted
the same distance behind the mirror as the real object is in front
![](https://s3.amazonaws.com/brainscape-prod/system/cm/184/407/137/a_image_thumb.jpg?1459004050)
What are our brains hard wired to think?
our brains are hardwired to think that light travels in straight lines
we can be fooled to think the image behind the mirror because our brains do not know that the real rays of light have been reflected of the mirror and have changed direction
![](https://s3.amazonaws.com/brainscape-prod/system/cm/184/407/166/a_image_thumb.jpg?1459004026)
How do you construct ray diagram to illustrate the formation of a virtual image in a plane mirror?
- Draw the virtual image. The image is the same size as the real image and is the same distance behind the mirror as the real object is in front
- Draw a reflected ray going from the top of the virtual image to th top of your eye. Draw a bold line for the part of the ray between the mirror and eye, and a dotted line for the part of the ray between the mirror and the virtual image
- Draw an incident ray going from the top of the onject to the mirror. The incident and reflected rays follow the law of reflection - but you don’t have to measure any angles. Draw the ray from the object to the point where the reflected ray meets the mirror
- Now you have an incident ray and a reflected ray for the top of the image. Repeat steps 2 and 3 again for the bottom of the image - a reflected ray going from the image to the bottom of the eye, then an incident ray from the object to the mirror
![](https://s3.amazonaws.com/brainscape-prod/system/cm/184/407/365/a_image_thumb.jpg?1459004390)
The normal is always …o (parallel/perpendicular) to the mirror
The normal is always 90o (perpendicular) to the mirror
What is refraction?
refraction is the bending of light which occurs at the boundary of two different medium, due to a change of density which changes the speed of light - it occurs when light travels from one medium to another
‘changes direction’