Light - Reflection of Light

Question 1

Laws of Reflection

Answer 1

1. Angle of reflection (r) = Angle of incidence (i)

2. Incident ray, normal, reflected ray are all in same plane

Question 2

Parallax

Answer 2

1. Apparent relative movement of two objects due to movement of the observer
2. Object that is farthest away appears to move with the observer

Question 3

Self-luminous object

Answer 3

Object that gives out its own light

Question 4

Non-luminous object

Answer 4

Does not give out its own light

Question 5

Converging beam

Answer 5

Beam of light getting narrower

Question 6

Diverging beam

Answer 6

Beam of light spreading out (like the light from a torch)

Question 7

Parallel beam

Answer 7

Beam of light that remains the same width

Question 8

Reflection of light

Answer 8

Bouncing of light off an object is called reflection

/light rebounding off surfaces

Question 9

Diffuse reflection

Answer 9

If surface is rough, reflected light is scattered in all directions

Question 10

Regular reflection

Answer 10

If surface is silvered + polihed smooth (eg. mirror), light falling on it is not scattered in all directions (it is reflected off)

Question 11

Real image

Answer 11

Formed by the actual intersection of light rays, (can be seen on a screen)

Question 12

Virtual image

Answer 12

Apparent intersection of light rays, can never be seen on a screen, but can be located by no parallax

Question 13

Concave mirror formula for real image

Answer 13

in hardback

Question 14

Concave mirror formula for virtual image

Answer 14

in hardback

Question 15

Convex mirror formula

Answer 15

in hardback

Question 16

Magnigication formula

Answer 16

on hardback

Question 17

Convex mirror

Answer 17

Image is always virtual and diminished

Question 18

Incident ray

Answer 18

Ray of light falling on mirror

Question 19

Reflected ray

Answer 19

Ray of light leaving the mirror

Question 20

Normal at the point of incidence

Answer 20

Line drawn perpendicular to the mirror where ray strikes the mirror

Question 21

Angle of incidence

Answer 21

Angle between incident ray + the normal

Symbol is i

Question 22

Angle or reflection

Answer 22

Angle between reflected ray + the normal

Symbol is r

Question 23

Without light you cannot see

Answer 23

To be able to see an object, light from object must enter your eye

Question 24

Self-luminous object

Answer 24

Object that gives out its own light eg. the Sun, stars, fire, a bulb

Question 25

Non-luminous object

Answer 25

Object that does not give out its own light eg. when light from some other source bounces off object + goes into your eye

Question 26

Light

Answer 26

- A form of energy | - Travels away from source producing it

Question 27

How we know light is a form of energy

Answer 27

1. Other forms of energy is always needed to produce light eg. electrical energy is converted to light energy in a bulb 2. Light can cause a photocell to produce electric current eg. solar panels 3. Light shines on Crooke's radiometer, vanes rotate (converts light energy to kinetic energy)

Question 28

Light travel

Answer 28

Light travels in straight lines

Question 29

Diverging beam

Answer 29

Beam of light spreading out (like light from a torch)

Question 30

Converging beam

Answer 30

Beam of light getting narrower

Question 31

Parallel beam

Answer 31

Beam of light that remains the same width

Question 32

Light ray

Answer 32

Straight line showing direction in which light is travelling | Very narrow parallel beam is a light ray since it is a straight light showing direction in which light is travelling

Question 33

Reflection

Answer 33

Bouncing of light off an object

Question 34

Use of plane mirrors

Answer 34

1. Used to see yourself | 2. Periscope

Question 35

Speed of light

Answer 35

3 x 10^8 m s^-1

Question 36

where is light detected in the eye?

Answer 36

retina

Question 37

two invisible parts of the electromagnetic spectrum with shorter wavelength than visible light

Answer 37

- ultraviolet - x-rays - gamma rays

Question 38

pairs of complementary colours of light

Answer 38

red and cyan green and magenta blue and yellow

Question 39

concave mirrors, rather than convex mirrors, are used by dentists to examine teeth. Explain why

Answer 39

to give a magnified image

Question 40

a diverging lens cannot be used as a magnifying glass. Explain why

Answer 40

diminished image always formed

Question 41

diagram of the path of light through a lens close up

Answer 41

know

Question 42

why each fibre (fibre optic) is coated with glass of lower refractive index

Answer 42

so total internal reflection occurs and no light escapes

Question 43

When underwater: why does the cornea not act as a lens

Answer 43

- light not refracted at cornea | - water and cornea have same n value

Question 44

When underwater: what is the max power of the eye?

Answer 44

maximum power of the internal lens

Question 45

When underwater: why do objects appear blurred?

Answer 45

-internal lens not powerful enough to focus light on retina / light not brought to a focus on the retina

Question 46

When underwater: how wearing goggles allows objects to be seen clearly

Answer 46

- light refracted on passing from air to cornea | - cornea now acts as a lens