PAG 8- EM waves and matter

Question 1

what is the incident ray?

Answer 1

light ray travelling towards a surface

Question 2

what is the normal line?

Answer 2

line that is perpendicular to a surface

Question 3

what happens when the incident ray is absorbed?

Answer 3

the light is absorbed and converted into heat energy

Question 4

what is the angle of incidence?

Answer 4

the angle at which the light enters

Question 5

what is the angle of reflection?

Answer 5

the angle at which the reflected ray bounces off a surface

Question 6

what happens when the incident ray is reflected??

Answer 6

-the wave bounces off the surface
-the angle of reflection is equal to the angle of incidence

Question 7

what is the law of reflection?

Answer 7

the angle of reflection is equal to the angle of incidence

Question 8

what happens when the incident ray is refracted?

Answer 8

when light travels from a less dense to a more dense medium, the angle of refraction is smaller than the angle of incidence

Question 9

describe dispersion of light

Answer 9

When white light rays are refracted by a triangular glass prism they are split into a spectrum. Red light is the longest wavelength wave and experiences the least change in velocity, so it refracts the least. Violet is the shortest wave and experiences the greatest change in velocity, so it refracts the most. This is called dispersion.

Question 10

what are the independant variables for
PAG 8- EM waves and matter?

Answer 10

angle of incidence

Question 11

what are the dependant variables for
PAG 8- EM waves and matter?

Answer 11

angle of refraction

Question 12

what are the control variables for
PAG 8- EM waves and matter?

Answer 12

-position of plastic block
-intensity of light

Question 13

what is the method for PAG 8- EM waves and matter?

Answer 13

1. connect the ray box to a power pack in order to produce a slim light ray
2. place the Perspex block on the sheet
3. use the guidance on the sheet to help you shine the light ray on the block in the correct angle
4. use a pencil to make a mark on the sheet where the light ray leaves off the block
5. repeat steps 3 & 4 for different angles of incidence
6. use a ruler to draw straight line from the point where all the incident rays meet, to each of the marks on the paper

Question 14

why is it important to place the block in the right place for PAG 8- EM waves and matter?

Answer 14

in order to have an accurate angle of incidence

Question 15

what safety precautions did you take for PAG 8- EM waves and matter?

Answer 15

-hot light bulb (burns)- grab raybox from sides
-glass light bulb (cut if breaks)- handle with care
-light source (damage eyesight)- don’t look directly into it

Question 16

what is the conclusion for PAG 8- EM waves and matter?

Answer 16

the angle of refraction is smaller than the angle of incidence as light travels from air to plastic

Question 17

what are two possible sources of error for PAG 8- EM waves and matter?

Answer 17

-angle of incidence not accurate because of light ray from ray box
-plastic block not aligned well
- marks on paper for refracted rays not accurate

Question 18

what are two ways to improve my experiment for PAG 8- EM waves and matter?

Answer 18

-light intensity should increase to produce a brighter light ray, use a smaller slit that produces a thinner ray
-try to place the block in the right position
-repeat the process a couple of times for each angle of incidence