Light Flashcards
(32 cards)
What are luminous objects?
Sources of light
Luminous objects produce their own light.
What are non-luminous objects?
Do not produce their own light
Non-luminous objects rely on external light sources.
When light hits an object, what are the three possible outcomes?
• Absorbed
• Reflected
• Transmitted
What happens when light hits a transparent object?
Most light is transmitted
Transparent objects allow light to pass through with little scattering.
What happens when light hits a translucent object?
Light is scattered
Translucent objects allow some light to pass but scatter it.
What happens when light hits an opaque object?
No light is transmitted, so a shadow is produced
Opaque objects block light completely.
Through which mediums can light travel?
Gases, some solids, liquids, and a vacuum
Light can travel through empty space.
What is the speed of light in a vacuum?
About 300,000 km/s
What is a light-minute?
The distance light travels in one minute
What is a light-year?
The distance light travels in one year
What effect does a prism have on light?
Refracts different colours of light by different amounts
This creates a continuous spectrum of colours.
What are the primary colours of light?
• Red
• Green
• Blue
What are secondary colours of light?
Produced when any two primary colours are mixed
Examples include yellow (red + green) and magenta (red + blue).
What do filters do to colours in white light?
Subtract colours so that only one colour is transmitted
How do objects appear to be different colours?
They reflect some colours of light and absorb others
What do black objects do with light?
Absorb all colours
What do white objects do with light?
Reflect all colours
What does the law of reflection state?
The angle of incidence is equal to the angle of reflection
What is refraction?
Light changes direction when it travels from one medium to another
Why does refraction occur?
Because light travels at different speeds in different materials
What happens to light rays when they slow down?
They are refracted towards the normal
What happens to light rays when they speed up?
They are refracted away from the normal
What type of images do mirrors produce?
Virtual images that look like they are behind the mirror
What is the role of lenses in light manipulation?
Use refraction to spread out or focus light
