Optics Review Flashcards
(34 cards)
What are the 7 different categories of the electromagnetic spectrum
- Radio
- Microwaves
- Infarred
- Visible light
- UV rays
- X-rays
- Gamma rays
What are Gamma rays used for?
Cancer treatment
Sterilization
Nuclear energy
What are Infared rays used for
Remote controls
Lasers
Heat detection
List the 7 different colours from least to most energetic
- Red
- Orange
- Yellow
- Green
- Blue
- Indigo
- Violet
How are UV rays useful to humans
Supplying vitamin D
Killing bacteria
What is incandescence? What are two examples of incandescence
Incandescence is the production of light from heat
Lava
Sun
How do objects glow in the dark?
By storing UV energy and slowly releasing it as visible light energy
Describe electric discharge. What are two examples of light from electric discharge
Electric discharge creates light when electrical currents pass through a gas
Neon lights
Lightning
What is the difference between phosphorescence and fluorescence?
Phosphorescence stores UV light and releases it slowly to produce light. fluorescence releases visible light due to the absorption of UV rays
Explain Chemiluminescence. How do glow sticks create light?
Chemiluminescence is the mixing of different chemicals to create light that does not produce any heat (cold light)
Glow sticks mix different chemicals when you crack them to release light without producing heat
What is bioluminescence? Give five organisms that use it
Bioluminescence is Chemiluminescence in living organisms
Fireflies, Anglar fish, algae, bacteria, Jellyfish
Why would these animals need to use bioluminescence?
For protection against predators, finding mates, and for visuality (seeing at night)
What does LASER stand for? And how do they work?
Light
Amplification
Stimulated
Emission
Radiation
Emit electromagnetic waves of the same energy levels to create one colour
What does LED stand for? How do they work?
Light
Emitting
Diode
LEDs send a current through a semi conductor to produce light without producing heat
State the two laws of reflection
The angle of incidence is always equal to the angle of reflection
The incident ray, normal, and reflected Ray are all on the same plane
Define Specular reflection
A reflection on a smooth or regular reflective surface
Define diffuse reflection
A reflection on a rough or irregular reflective surface
Define refraction
Bending or change in direction of a light ray as it passes through a different medium
State the two rules of refraction
- The incident ray, the refracted ray, and the normal at the point of incidence all lie in the same plane
- The ratio of the sine of angle I to the sine of angle R is constant for the pair of given media
What causes refraction
The slowing down of a light ray through a new medium
Define critical angle
When light is passing from a slow medium to a fast medium the angle of refraction continues to increase as the angle of incidence increases
What two conditions need to be met for total internal reflection to occur?
- Light is travelling more slowly in the first medium than in the second
- The angle of incidence is large enough that no refraction occurs in the second medium. Instead the ray is reflected back into the first medium
Why do diamonds sparkle so much?
Diamonds when cut properly reflect light inside them and then the light rays bounce around inside before exiting through the top of the diamond
How do fiberoptic cables work?
They transmit data by fast travelling pulses of light through a glass tube causing the pulses to reflect internally until they reach their destination
