Reflection Refraction And Diffraction Flashcards
In what three ways can the direction of travel of a wave be changed when it meets an obstacle?
Reflection
Refraction
Diffraction
What is reflection?
Reflection of light is what allows us to see objects as light bounces off them into our eyes
What happens when light traveling in the same direction reflects off an uneven surface such as a piece of paper?
The light reflects off at different angles
What happens when light traveling in the same direction reflects from an even surface such as a mirror?
It’s all reflected at the same angle and you get a cleat reflection
What is the law of reflection that applies to every reflected ray?
Angle of incidence = angle of reflection
How is an image formed in a plane mirror (ray diagram)
The image is the same size as the object
It is as far behind the mirror as the object is in front
The image Is virtual and upright (virtual because the object appears to be behind the mirror)
The image is laterally inverted
What does laterally inverted mean?
The left and right sides are swapped
How do you draw a ray diagram for a plane mirror?
draw the virtual image (same size and equidistant from the line)
Draw a reflected ray from top of virtual image to top of eye and a dotted line for the part of the ray between the mirror and the virtual image
Draw an incident ray from top of the object to the mirror
Do the same for the bottom of the eye
What is refraction?
When waves go through a new material but change direction
What is diffraction?
When the waves bend round the obstacle causing the waves to spread out
What happens to the waves during diffraction?
All waves spread out at the edges when they pass through a gap or pass an obstacle
What does the amount of diffraction depend on?
The size of the gap relative to the wave length of the wave
The narrower the gap or the longer the wave length the more the waves spread out
When does a wave change direction (refraction)?
When it crosses a boundary between two substances eg from glass to air
What happens
À) if a light wave hits the boundary face on and
B) if a light wave hits a different medium at an angle
À) It carries on in the same direction
B) the wave changes direction as it is refracted
What happens when light shines on a glass window pane?
Some of the light is reflected but a lot of it passes through the glass and gets refracted in the process
