reflection and refraction

Question 1

when does reflection happen?

Answer 1

when a wave changes direction back to the same medium at a boundary

Question 2

what is reflection normally represented on?

Answer 2

a ray diagram

Question 3

what is the normal?

Answer 3

an imaginary line which we measure angles from that is always perpendicular to the boundary

Question 4

what is the angle of incidence?

Answer 4

the angle the incidence ray makes with the normal

Question 5

what is the angle of reflection?

Answer 5

the angle the reflected ray makes with the normal

Question 6

what is the law of reflection?

Answer 6

the angle of incidence is equal to the angle of reflection

Question 7

when does refraction happen?

Answer 7

when a wave changes direction when travelling into a different media at a boundary

Question 8

what of a wave changes when refracted?

Answer 8

the speed and wavelength- not the frequency

Question 9

the normal is at what type of angle to the boundary?

Answer 9

right angles

Question 10

from less dense (eg glass to air) what happens to the light?

Answer 10

it bends TOWARDS the normal

Question 11

from more dense to less dense (eg glass to air) light….

Answer 11

bends AWAY from the normal

Question 12

when light passes into a denser substance what happens to the rays?

Answer 12

the rays will slow down

Question 13

what is the independent variable in the refraction of light practical?

Answer 13

shape of the block

Question 14

what is the dependant variable in the refraction of light practical?

Answer 14

direction of refraction

Question 15

what are the control variables in the refraction of light practical?

Answer 15

the width of the light beam and the same frequency/ wavelength of the light

Question 16

why will we need a ray box?

Answer 16

to provide a narrow beam of light to reflect in the mirror

Question 17

why will we need a protractor?

Answer 17

to measure the light beam angles

Question 18

why will we need a sheet of paper?

Answer 18

to mark with lines for angle measurement

Question 19

why will we need a pencil?

Answer 19

to mark perpendicular lines and angle lines on paper

Question 20

why will we need a ruler?

Answer 20

to draw lines on paper

Question 21

why will we need a rectangular block, semi- circular block and a prism?

Answer 21

to refract the light beam

Question 22

1st step of the practical?

Answer 22

place the glass block on a sheet on paper and draw around it using a pencil

Question 23

2nd step?

Answer 23

switch on the ray box and direct a beam of light at the side face of the block

Question 24

3rd step?

Answer 24

mark on the paper:
a point on the ray close to the ray box
the point where the ray enters the block
the point where the ray exits the block
a point on the exit light ray which is a distance of about 5cm away from the block

Question 25

4th step?

Answer 25

draw a dashed line normal to the outline of the block where the points are

Question 26

5th step?

Answer 26

remove the block and join the points marked with 3 straight lines

Question 27

6th step?

Answer 27

replace the block within its outline and repeat the above process for a ray striking the block at a different angle

Question 28

7th step?

Answer 28

repeat the procedure for each shape of block- the prism and the semi- circle