revision

Question 1

what is reflection?

Answer 1

when light bounces off a surface

Question 2

what surfaces reflect

Answer 2

usually opaque and translucent surfaces

Question 3

define translucent, transparent, and opaque

Answer 3

transparent=light can go fully go through the substance
translucent=some light can go through a substance
opaque=no light can pass through

Question 4

define luminous and non luminous

Answer 4

a luminous object is one that makes and gives off its own light
a non-luminous object is one that does not make its own light

Question 5

what is the incident ray

Answer 5

is the in going beam of light hat hits the mirror

Question 6

what is the reflected ray

Answer 6

beam of light that bounces off the mirror

Question 7

what is the angle of incidence

Answer 7

between the incidence ray and the normal

Question 8

angle of reflection

Answer 8

angle between the reflected ray and the normal

Question 9

what is the law for reflection

Answer 9

angle of incidence = angle of reflection (I=r)

Question 10

what is refraction

Answer 10

is when light bends at a surface between two different substances.

Question 11

in refraction when is a ray bent towards the normal?

Answer 11

light rays bend towards the normal when light travels from a less dense to a more dense substance e.g. air into glass or air into water

Question 12

in refraction when is a ray bent away from the normal

Answer 12

light bends away from the normal when light travels from a more dense to a less dense substances e.

Question 13

what type of lens is diverging? converging?

Answer 13

convex is converging-light beams come together
concave is diverging=light beams move apart

Question 14

what are the colours in the visible spectrum

Answer 14

ROYGBIV

Question 15

Visible spectrum energy

Answer 15

red=low ow frequency through to violet which is high frequency/energy

Question 16

what is the speed of light

Answer 16

300,000 km/sec

Question 17

what is a light year

Answer 17

a light year is the distance light can travel in one year

Question 18

how far does light travel in air in one hour

Answer 18

300,000 x 60 x 60 = 1,080,000,000

Question 19

what is a photon and how is it made

Answer 19

a photon is a small packet of energy. It is made when electrons in an atom are energized by an external source of energy such as heat, electricity, light , UV, and gets `excited’ and jump up one electron shell. As they fall back they release a bit of extra energy as a photon of light

Question 20

list different forms of energy that can excite electrons in atoms to make photons

Answer 20

heat, electricity, light, UV

Question 21

what kind of wave is an electromagnetic wave

Answer 21

transverse

Question 22

what is the wave equation

Answer 22

v=flanda

Question 23

what is the velocity(speed)

Answer 23

how fast the wave is travelling measured in metres per second

Question 24

what is wave frequency

Answer 24

is the number of waves that pass a particular point every second. it is measured in hertz

Question 25

what is the wavelength

Answer 25

is the distance from the peak of one wave to the peak of the next wave measured in metres

Question 26

what is the wave amplitude

Answer 26

height of the wave from top to bottom measured in metres

Question 27

how does an eye use a lens to focus light

Answer 27

light passes through the pupil and into the lens. As it passes through the lens which is convex shape, the light is converged onto the back of the eye. the retina where it changes to an electrical signal that travel through the optic nerve to the brain .the lens of the eye is attached to a ciliary muscle that can tighten or relax the lens making it thinner or fatter depending on how far away the objects are that a person is looking at. This allow the eye to focus the images sharply and clearly on the back of the retina.

Question 28

what is electromagnetic radiation

Answer 28

a kind of radiation including visible light, radio waves, gamma rays, and X-rays, in which electric and magnetic fields vary simultaneously.

Question 29

What is wave motion

Answer 29

transfer of energy without matter

Question 30

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Answer 30

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Question 31

refraction

Answer 31

is when light bends at a surface between two different substances.

Question 32

why does refraction occur

Answer 32

light travels at different speeds through different substances the difference in speed results in different amounts of bending or refreaction

Question 33

what is a lens

Answer 33

is a transparent piece of plastic or glass which is shaped to curve inwards and outwards

Question 34

concave and convex

Answer 34

convex =out concave=in