Light

Question 1

how fast does light travel through space?

Answer 1

300,000 km per second

Question 2

what is light made up of?

Answer 2

light is made up of particles called photons that travel in waves

Question 3

define luminous and give examples

Answer 3

luminous objects release light on their own. e.g torch, laser, light bulb

Question 4

define incandescent and give examples

Answer 4

objects that release light because they are hot. e.g sun, flames and lava

Question 5

define non-incandescnet and give examples

Answer 5

objects that release light without getting hot. e.g glow worms, fire flies and glow sticks

Question 6

define transmitted and give examples

Answer 6

when light passs through the objects. e.g air, glass and water

Question 7

define reflected and give examples

Answer 7

when light bounces off the object. e.g mirror, foil, jewellery

Question 8

define absorbed and give examples

Answer 8

when light is taken into the object. e.g table, paper and chair

Question 9

law of reflection

Answer 9

when light is reflected from a flat, smooth surface, it bounces away from the surface at the same angle from which it came from.

Question 10

define refraction

Answer 10

the bending of light as it passes from one material to another

Question 11

define refractive index

Answer 11

a measure of how light bends as it passes from one substance to another- change in speed

Question 12

when does light not bend?

Answer 12

when it enters a new medium at 90 degrees to the surface.

Question 13

define dispersion

Answer 13

the splitting of white light into colours

Question 14

what colours experience more dispersion

Answer 14

violet and blue slowed more and experience more bending than orange and red

Question 15

cornea

Answer 15

The cornea bends light into the lens and lies in front of the iris. It is clear

Question 16

iris

Answer 16

A muscle controlling how much light enters the eye suspended in between the cornea and lens. Comes in many colours.

Question 17

pupil

Answer 17

A dark circle in the centre of the iris. A hole that lets light into inner eye. They are round.

Question 18

lens

Answer 18

A flexible structure that enables light to be focused on the retina

Question 19

aqeous humour

Answer 19

A clear, watery fluid produced by the ciliary body that lies between cornea and lens. It lubricates the cornea and lens.

Question 20

ciliary muscle

Answer 20

It is connected to the lens and the ciliary muscle changes the shape of the lens.

Question 21

vitreous humour

Answer 21

A clear fluid between the lens and retina

Question 22

sciera

Answer 22

The white of the eye

Question 23

retina

Answer 23

Absorbs the light rays and turns them into electrical signals

Question 24

optic nerve

Answer 24

Carries the electrical signals from the retina into the brain

Question 25

choroid

Answer 25

rich blood supply that nourises the retina

Question 26

what happens when light passes through a bioconvex lens

Answer 26

converges towards a focal point

Question 27

accomodation

Answer 27

changing the lens shape to form a sharp image on the retina

Question 28

what kind of lenses need to be used with short sightedness

Answer 28

concave lenses so the light rays are diverged in front of the retina

Question 29

what kind of lenses need to be used with long sightedness

Answer 29

convex lenses need to converge the light to focus the image on the retina

Question 30

converge

Answer 30

when parallel light rays close in towards a focal point

Question 31

diverge

Answer 31

when a beam of parallel light rays spread out. there is no focal point. the diverging rays can be traced backwards until they intersect at a virtual focal point