Chapter 6 Flashcards
What is luminous object?
Object that produces its own light
What’s an illuminated object?
Object that reflects light
##footnote##
illuminated is nonluminous. Nonluminous isn’t always illuminated.
When does reflection occur
When a light ray bounces off an object
Diagram ppt
Open this please.
What are the 2 angles and rays called? (Reflecting)
Angle of incidence, angle of reflection, incident ray and reflected ray.
The dashed line is called?
Normal
Meaning of medium?
Material
What is refraction?
Change in direction of light when passing from one medium to another Due to change of speed.
Air has more/less density than water.
Less
Refracted ray is toward/ away from the normal?
a) air to water/glass
b)water/ glass to air
c) water to glass
d) glass to water
a) toward the normal
b) away from the normal
c) toward the normal
d) away from the normal
Which medium does light travel fastest through?
Air
What is dispersion
Process of splitting of white light to seven spectrum colours
What is an example of dispersion happening?
White light passing through a trianglar glass prism
What seven colours are they?
ROY G BIV. Red Orange Yellow Green Blue Indigo Violet
##footnote## they are merged together
Who discovered the splitting of white light? When?
Issac Newton in 1666
How do rainbows from after/during rain?
- Refraction from sky to water droplets
- Internal reflection
- Dispersion and refraction
##footnote## yiu have to be behind the sun to see the rainbow cuz of reflection of internal reflection in water droplets
-Red is smallest/largest angle of refraction.
-violet is smallest/largest angle of refraction.
Red is smallest, violet is largest
Why is red smallest angle?
It’s the fastest light
What are the 3 primary colour of light and what colour is created when they’re merged together?
Red, blue, green, they form white light
What are the secondary colours?
Red+Green= Yellow
Blue+Red=Magenta
Green+Blue=Cyan
RGY, BRM,GBC
What colour appears when the secondary colour are mixed?
Black
What happens to white light when you put a magenta filter and a cyan filter after each other?
Magenta is transmitted after white light passes through 1st filter. Then magenta(blue+red) passes through cyan(green+blue) filter. Blue is end product.
Can it travel though matter?
(Light and sound)
Yes, they both can
Can it travel through a vacuum?
(Light and sound)
Light can but sound can’t
How are they detected?
(Sound and light)
Sound==> ears and microphones
Light==> eyes and cameras
Can it be reflected?
(Light and sound)
Yes (echoes and mirrors)
Can it be refracted?
(Light and sound)
Yes
Which is faster?
(Sound and light)
Light
What material is need for regular/irregular reflection to occur?
Plane mirror for regular reflection.
Nonplane for irregular reflections
What is a spectrum?
Range of colours in white light
What is the meaning of primary colours of light?
Colours that cannot be made by mixing any other colours of light
What is the difference between primary colours of light and primary colours?
The colours of light mix differently than the colours in paint
How many colours maximum can a phone/device show?
256
Difference between transmitted and reflected?
Transmitted is when it’s a filter so light passes through the medium. Reflected is used when an object is shown to have this colour
What makes things look differently colour wise
According to what they absorb and reflect
What happens when an object doesn’t have any colours of light reflected?
It appears black
What happens when blue and red filters are put after each other
No light is transmitted
Why does a white t-shirt appear red in red light?
White t-shirt reflects red light
Why does a red ball appear red in white light?
It absorbs all 6 colours and reflects only red, thus appearing as red object
What is a rule in reflection? (Diagrams)
Angle of incidence= Angle of reflection
Which is bigger? (Galaxy or universe)
Universe
What is the meaning of universe?
Space and everything in it
What is the meaning of Galaxy?
Group of stars bound together by gravity
What is one factor that gravity is affected by?
Mass increase
What is stellar dust?
Dust found in space
What are the three types of Galaxies?
Spiral, elliptical, irregular
What is our Galaxy called? What type is it?
Milky way. It is spiral.
What is the closest Galaxy to us called? What type is it?
Canus major dwarf. Elliptical.
How many galaxies are there approximately?
100-200 million
Why are the stars that we see in the milky way?
Closest to earth
How much of our Galaxy can we see?
One arm of the spiral
How does our Galaxy look like?
A milky band
Why can’t we know accurately the number of stars in our Galaxy?
We can’t see all of them
How much stars are there in our galaxy?
250 million stars approximately
What is definition of asteroids?
Small, rocky, irregularly shaped objects that orbit the sun
What are asteroid belts?
Place where asteroids orbit
Where do asteroids come from?
Leftovers from formation of solar system
Where’s the asteroid belt?
Between Mars and Jupiter
What is the largest asteroid discovered yet?
Ceres
What is the smallest asteroid yet?
Itokawa
How might some asteroids change shape?
Affected by the tidal forces
What’s difference between comets and asteroids
Comets have ice cores
Ceres was considered a planet. Why?
It has core, mantle and crust. It has craters. It is a sphere.
Why isn’t Ceres a plant?
Too small
What happens when asteroids hit the earth?
- Dust and smoke enter the atmosphere
- Decreasing temperature because it blocks the sun
Why do asteroids hit earth?
- Earth’s strong gravity
- Some asteroids have orbits that are closer to earth
