Reflection, Refraction And Total Internal Reflectin

Question 1

What happens when waves hit a surface

Answer 1

Waves can either be:
- transmitted through a material (pass through)
- absorbed by a material
- reflected off of the surface of the material
- refracted if travel through a denser or less dense medium

Question 2

Describe reflection

Answer 2

• and incident ray hit a surface
• a dotted line is drawn straight up where it hits the surface, this is the normal
• the angle between the incident ray and the normal is called the angle of incidence
• the angle of incidence if always equal to the angle of reflection
• so the reflected ray is drawn at the same angle on the other side of the normal
  (Arrows must be drawn to show the direction of both rays)
• the image produced in a plane mirror is virtual, upright and inverted

Question 3

Describe refraction

Answer 3

• waves change direction when they change speed, moving from one medium to another
• when a waves enter a denser medium its velocity decreases so it slows down
• a normal is drawn straight up from the point where the incident ray meet the surface
• when waves slow down, they bend towards the normal so the refracted ray bends inside the object
• when the waves pass from the dense object back into the air, their velocity increases again so it’s bend away from the normal
• if the waves enter the surface at the normal (at a right angle to the surface) they don’t change direction