Light & Optical Instruments Flashcards
How is light produced?
A chemical reaction or it comes naturally for example from the sun.
Define light.
Form of energy that we can see.
Name some natural and artificial sources of light
Natural sources.
Sun stars and fire.
Artificial sources.
Lightbulbs flashlights etc.
Why are fluorescent tubes more energy efficient than incandescent bulbs ?
Fluorescent tubes don’t create thermal energy and you can touch them when they’re lit so therefore it saves more energy
How does light travel?
Light travels in a straight line/path
Describe what happens to light when it strikes different surfaces.
When light hits an opaque surface it cannot travel through. When it hits a translucent surface after passes through, afterwards it goes into other directions but when it hits a transparent surface it goes straight through without changing direction.
Give some examples of a luminous object.
Lightbulb, Candle flame, Christmas lights, certain animals (example some jellyfish and fireflies).
List some nonluminous objects.
Door frame, glass, paper etc.
State the laws of reflection
- the angle of reflection (r) is equal to the angle of incidence (i)
- the incident ray the normal and the reflected ray are always in the same plane
Know how to draw and show how a plane near produces an image that is the same size as the reflected object
Page 222 figure 7.16, 7.17 and 7.18
Explain what causes refraction of light rays.
Refraction of light rays happen when the bending of light travels to one medium to another.
The bending of light as it passes from one medium to another
Refraction
Can be transformed to chemical, thermal and electrical energy
Light
Allowing no light to pass through
Opaque
An artificial light source
Incandescent bulb
The type of diagram explaining how light travels
Ray diagram
Occurs when light bounces off a surface
Reflection
Describes objects that can produce their own light
Luminious
Why do people preferred where light-colored clothing’s out in the summer
People prefer her to her like colored clothing in summer because like colors don’t absorb as much light compared to dark colours. and it makes you hot when the light is absorbed
What are some things you can do or say to give meant to say when the light travels in a straight line/path
You could shine a light against the wall and put your hand between the light and the wall and look at your shadow, your shadow should prove the rest
Name a sources of light you have learned about in this chapter and give an example of each
In this chapter I learned about five sources of light: incandescent source [example lightbulb] , fluorescent sources [example fluorescent tube], phosphorescent [sources example darkroom timer], chemiluminescent sources [example a glow stick], bioluminescent sources [example of fireflies]
What properties message surface have if the light that reflects from it forms a clear image of an object
The surface must be smooth flat and reflecting
Your vision involves more than your sense of sight. Explain.
Not only do you need your sense of sight to see you but you also need light to see because without light you wouldn’t be able to see the object because the light reflection on it.
When sunlight travels from the vacuum of space, into earth’s atmosphere it slows down slightly. Why? What behavior of what occurs?
When sunlight travels into the earth’s atmosphere is slows down slightly because when the sunlight hits the normal it bends towards it and slows down slightly.
