Light Phenomena + Shadow Formation

Question 1

what is light?

Answer 1

a form of energy which we can detect with our eyes

Question 2

luminous + example

Answer 2

materials which emit light (sun, light bulb)

Question 3

non-luminous +example

Answer 3

materials which can be seen when they reflect light (water, moon)

Question 4

reflection

Answer 4

light bouncing off shiny materials (mirrors)

Question 5

refraction

Answer 5

light bends when going from one medium to another (spoon in water)

Question 6

dispersion

Answer 6

light splits into its basic colors when passing through a prism (rainbow, oil)

Question 7

absorption

Answer 7

light being absorbed by objects (black sweater)

Question 8

diffusion

Answer 8

light spreads in many directions as it is emitted from a source (light bulb)

Question 9

diffraction

Answer 9

light bends through small openings giving a non uniform image

Question 10

how does light move and what is this called

Answer 10

in a straight line (called linear propagation) - proves why shadows have sharp edges

Question 11

how are shadows formed

Answer 11

when an obstacle blackens the light rays

Question 12

what happens when the distance from the obstacle to light source is equal to the distance of obstacle to the screen

Answer 12

the area of the umbra is equal to the area of the penumbra

Question 13

what happens when the distance is smaller from the obstacle to light source than from the obstacle to the screen

Answer 13

the area of the umbra is less than the area of the penumbra

Question 14

what happens when the distance is bigger from the obstacle to light source than from the obstacle to the screen

Answer 14

the area of the umbra is larger than the area of the penumbra