visible light

Question 1

what is luminous?

Answer 1

an object that gives off light or glows in dark

Question 2

what is illuminated?

Answer 2

lit up

Question 3

what is visible light?

Answer 3

• an object that comes from a luminous source
• can be observed by the naked eye

Question 4

what is radiation?

Answer 4

the process where light moves away from its origin.

Question 5

how is light transferred?

Answer 5

by radiation.

Question 6

what happens when lights are switched on?

Answer 6

room becomes illuminated because bulb radiates in all directions.

Question 7

why cant you see around a corner?

Answer 7

light travels in straight lines

Question 8

what is a ray diagram?

Answer 8

a simplified way to show how light is radiated from a luminous object

Question 9

what is a pinhole camera?

Answer 9

• a pinhole camera illustrates that light travels in straight lines
• forms an upside down image of a luminous object on a screen

Question 10

what is the speed of light?

Answer 10

aproximateley 300 000 km per second

Question 11

what is the distance from the earth to sun?

Answer 11

150 million km

Question 12

what is the formula for distance?

Answer 12

time (seconds) x speed (km)

Question 13

what is the formula for time?

Answer 13

distance (km) divided by **speed **(km/s)

Question 14

what is the formula for speed?

Answer 14

distance (km) divided by time (seconds)

Question 15

what is white light?

Answer 15

the combination of all the different colours of light

Question 16

what is a spectrum of visible light?

Answer 16

the full collection of coulors that make up white light

Question 17

what is light called?

Answer 17

a wave

Question 18

what is a wave?

Answer 18

a pattern created by the repeated up and down or side to side movement of a medium which flows through it.

Question 19

what is a wavelength?

Answer 19

the length of one wave pattern

Question 20

what is frequency?

Answer 20

the number of waves that move past a certain point in one second

Question 21

what is white light made up of?

Answer 21

violet, indigo, blue, green, yellow, orange and red

Question 22

which colour has the shortest wave length?

Answer 22

violet

Question 23

which colour has the longest wave length and shortest frequency?

Answer 23

red

Question 24

what is light refraction?

Answer 24

the ability of a wave to change direction or bend when it passes from one medium to the other

Question 25

what happens when light shines on triangular prism?

Answer 25

each colour has own angle thus splitting white light refracted + dispersed into seven colours

Question 26

what is an opaque substance?

Answer 26

object that doesnt allow light to travel through it

Question 27

what happens to opaque objects?

Answer 27

* light = absorbed or reflected * absorbed: light cannot travel further once reached * black objects absorb light

Question 28

where do shadows form?

Answer 28

the area behind opaque objects that recieve no light

Question 29

what are transparent substances?

Answer 29

objects where light is able to travel through the object it can be absorbed or reflected

Question 30

explain how we see colour

Answer 30

if you have a coloured object, the other colours of the spectrum besides the colour of object will be absorbed and the colour of the object will be reflected if all colour = absorbed, object = black if all colour= reflected, object = white

Question 31

explain how you see yourself in the mirror

Answer 31

* light from light source reflects on you * this light shines on mirror * when light is reflected it always changes direction * light reflects back to your eye * your brain reads that light ray traveled length of the two light rays together * the brain forms image a distance away

Question 32

what is the normal?

Answer 32

imaginary line on reflective surface that forms 90 degree angle on surface

Question 33

what is an incident ray?

Answer 33

light that travels through the reflective surface

Question 34

what is the reflected ray?

Answer 34

the light that is reflected from the the reflected surface

Question 35

what is the angle of incidence?

Answer 35

angle measured from the normal to incidence ray.

Question 36

what is the angle of reflection?

Answer 36

angle measured from the normal to reflected ray. if surface = rough _then_ reflection = scattered.

Question 37

draw a ray diagram

Answer 37

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Question 38

draw refraction of light through a triangular prism

Answer 38

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Question 39

draw refraction of light through convex lens

Answer 39

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