P1 - Light and lasers Flashcards
1
Q
What does laser stand for?
A
Light Amplification by Stimulated Emission of Radiation.
2
Q
What is a laser?
A
A laser is a narrow intense beam of single colour.
3
Q
What are the main uses of lasers?
A
- communication
- dental treatment
- weapon guidance
- surgery
4
Q
How is a laser described?
A
- monochromatic
- low divergence
- coherent
- in phase
5
Q
How is information read off a CD by a laser?
A
The shiny surface of a CD contains billions of pits. The pattern of pits contains digital information. The laser light is reflected off the surface of the CD as the disk spins, and is detected by:
- the change in amount of light reflected
- no change
6
Q
What is total internal reflection?
A
The complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle.
