13) Light Flashcards
Define reflection.
Reflection is the bouncing of light off a surface.
The ray of light that hits the mirror surface is known as the _____ ray.
Incident Ray
The ray of light that bounces off the mirror surface is known as the _____ ray.
Reflected Ray
The imaginary line perpendicular to the mirror surface at the point of incidence is known as the _____.
Normal
The angle between the incident ray and the normal is known as the angle of _____.
Incidence, i
The angle between the reflected ray and the normal is known as the angle of _____.
Reflection, r
What are the characteristics of an image formed are observed when light rays are reflected off a plane mirror?
- Same Size
- Laterally Inverted
- Upright
- Virtual
- Distance between the image and the mirror = Distance between the object and the mirror
Define refraction.
Refraction is the bending of a light ray as it travels from one optical medium to another.
What is the Snell’s Law? (also known as formula for refractive index, n)
sin i / sin r = constant
i = angle of incidence
r= angle of refraction
Formula for Refractive Index. (using speed of light)
n = c / v n = medium c = speed of light in vacuum v = speed of light in medium
Define total internal reflection.
Total internal reflection (TIR) is the phenomenon that involves the reflection of all the incident light off the boundary.
State the 2 conditions needed for total internal reflection.
TIR only takes place when both of the following two conditions are met:
1) the light is in the optically more dense medium and approaching the optically less dense medium.
2) the angle of incidence is greater than the so-called critical angle.
Define critical angle.
The angle of incidence in the optically denser medium in which the angle of refraction is 90 degrees in the optically less dense medium.
Formula for critical angle
n = 1 / (sin c)
