reflection and diffraction

Question 1

what is the law of reflection

Answer 1

the fact that the angle of incidence equals the angle of reflection

Question 2

what is the angle of incidence

Answer 2

the angle between the normal and incident Ray

Question 3

what is the angle of reflection

Answer 3

the angle between the reflected Ray and the normal

Question 4

what is the normal

Answer 4

the imaginary line drawn at 90* to the reflecting surface

Question 5

describe a reflected image

Answer 5

a reflected image is

virtual
right way up
and same size

Question 6

what are the best surfaces to reflect

Answer 6

smooth surfaces produce strong echos when sound wave hit them and act as a mirror when light waves hit them. the waves are reflected uniformly (evenly) and can form images

rough surfaces scatter sound and light in all directions

Question 7

what can waves do in terms of reflection

Answer 7

they can be focuses to a point

they can appear to come from a point behind a mirror

Question 8

what is refraction

Answer 8

the change of direction of a light rat when it passes across a boundary between 2 dsubstances with different densities

Question 9

what do sound waves and light waves do in refraction

Answer 9

they change speed which causes them to change direction

but they bend back to the original direction once it leaves the block

Question 10

when wont refraction happen

Answer 10

reaction doesn’t happen if the waves cross the boundary at an angle of 90* (they carry straight on)

Question 11

what happens to the angle of refraction as u increase the angle of incidence

Answer 11

as you increase the angle of incidence you see a greater angle of refraction

Question 12

what is the critical angle

Answer 12

at a specific angle (42*) cannot refract any longer and just goes down the side of the block

Question 13

why does the light refract or bends towards the normal

Answer 13

light refracts or bends towards the normal because it slows down as it enters the glass

Question 14

why does light reflect and bend away from the normal

Answer 14

the light reflect and bend away from the normal because it speeds up as it goes from glass to air

Question 15

what happens when white light passes through a triangular prism

Answer 15

as it leaves the prison the different wavelengths of the individual xolours of light result in different angles of refraction

this splits the White light into the 7 colours of the rainbow this process is called dispersion. each colour of light can be called monochromatic

Question 16

is the angle of reflection bigger or smaller than the incidence angle

Answer 16

the angle of refraction is bigger than the incidence angle

Question 17

why is the angle of refraction bigger than the angle of incidence

Answer 17

because when the light moves from a substance to another substance where it moves faster it refracts and bends away from the normal

Question 18

what happens is the angle of incidence gets bigger than the critical angle

Answer 18

it doesn’t refract

instead it totally internally reflects

Question 19

what is an optical fibre

Answer 19

thin glass fibre used to send light signals along

uses totally internal reflection

Question 20

where do sound and light waves reflect reflect from

Answer 20

from surfaces

Question 21

what is diffraction

Answer 21

diffraction is the spreading out of waves when they pass through a gap round the edge of an obstacle