Reflection
The change in direction of a light ray when it bounces off a surface
Medium
The substance through which light travels
Ray
A straight line with an arrowhead that shows the direction of light waves
Fermat’s principle
Light follows the path that will take the least time
Incident ray
The ray of light that travels from the light source toward a surface
Angle of incidence
The angle between the incident ray and the normal in a ray diagram
Normal
A line that is perpendicular to the surface
Reflected ray
A ray that begins at the point where the incident ray and the normal meet
Angle of reflection
The angle between the reflected ray and the normal
Laws of reflection
- The incident ray, reflected ray, and normal always lie on the same plane
- The angle of reflection is equal to the angle of incidence
Plane mirror
A mirror with a flat, reflective surface
Virtual image
Images that appear to be coming from a certain position but are not actually from that position
What are the characteristics of virtual image?
- Upright
- Above the principal axis
- On the other side relative to the object
- Located behind the mirror
Real image
Image that appears inverted and below the principal axis
What are the characteristics of real image?
- Inverted
- Below the principal axis
-On the same side as the object - Located in front of the mirror
Characteristics of image
- Location (closer, farther, or same distance)
- Orientation (upright or inverted)
- Size (larger, smaller, or same size)
- Type (real or virtual)
How does stealth aircraft avoid radar?
- Uses a shape that ensures most radar rays will not return to the radar antenna, but rather to random directions
- Uses paint that absorbs energy from the radar waves by allowing them to penetrate the surface and reflect from one particle to the next, losing energy along the way until it is too weak for it to be detectable
