Optics Flashcards
A concave mirror magnifies or enables a wider angle?
Magnifies eg. Dentist mirror
Define rarefraction
When light goes through a denser material, it bends TOWARDS the normal.
Convex mirrors magnify or enable wide angle?
Enable wide angle. Eg. Security mirror
A virtual image is?
Cannot be captured on screen
A Real image is?
Can be captured on screen
Define Transparent
Fully allows light to pass through (glass)
Non luminous
Does Not produce it’s own light (moon)
Luminous
Produces it’s own light (sun)
Translucent
Partially allows light to pass through (bathroom mirror)
Opaque
Doesn’t not allow light to pass through (metal)
Why is a wall yellow?
When white light heats the wall, the yellow wave length is reflected, all other wave lengths being absorbed
To have clear sight, the image must be focused on what?
The retina
A thick lens has what?
A shorter focal length
A thin lens has what?
A longer focal length
For someone that is short sighted, what lens do they need?
A CONCAVE
For a longsighted, what lens do they need?
A CONVEX
What is the scattering of light?
Where the light is reflected against multiple substances, bouncing in so many directions.
This is different to the reflection of a plane mirror because wherever the light is reflected from the mirror, it bounces away from the surface in the same angle in which it came.
What are the two types of waves?
Transverse and compression
The angle of incidence is the same as?
The angle of reflection
Define iris
A thin circular structure in the eye
Responsible for controlling the diameter of the pupil, controlling the amount of light reaching the retina
Define cornea
- The cornea shields the rest of the eye from dust, germs etc.
- Controls the amount of oncoming light
- focuses 65-75%
Define pupil
The pupil controls the amount of light entering the eye
Define Lens
- Located behind the pupil
- provides fine tuning of focusing for reading the image
Define Optic nerve
Carries images from the retina the brain
Define Retina
Fine nerve tissue that transmits images to the brain
Light waves
- TRANSVERSE waves
- unable to travel through some substances but can travel through vacuum.
- speed in air 300 000 000m/s
Sound waves
- COMPRESSION waves
- travel through all liquids, solids, gases but not vacuum
- speed in air between about 330m/s and 350m/s depending on departure
