perform an activity to verify the Snell's law
Answers
Answer:
Set up apparatus as shown in the diagram.
Shine a ray of light onto the block.
With a pencil mark the incident and emergent ray.
Remove the glass block.
Draw the incident and emergent ray.
Then draw a line from where the incident ray meets the glass block to the emergent ray.
Answer:
Explanation:
Place the block in the middle of the A4 piece of paper so that its sides are parallel to each of the sides of the paper and draw around the block with a pencil to make its outline on the piece of paper.
Turn on the ray box and aim the light ray towards the block so that it makes an angle with the nearest surface of the block. For each piece of paper, change the angle of the incoming ray.
You will now need to mark on the paper, the path of the incoming and outgoing light rays. Do this by first drawing a dot on the paper somewhere along the incoming light ray. Now draw a second dot on the paper at the point where the incoming light ray hits the surface of the block. Do the same thing for the outgoing light ray; mark the point where it leaves the block and some other point along its path.
Now switch off the ray box and remove the block from the paper. Use a ruler to join the dots of the incoming ray. Now join the dots of the outgoing ray. Lastly, draw a line which joins the point where the incoming ray hits the block and where the outgoing ray leaves the block. This is the path of the light ray through the block.
The aim of this experiment is to determine the refractive index 2
n
2
of the unknown material using Snell's law which states 1sin1=2sin2
n
1
sin
θ
1
=
n
2
sin
θ
2
. We know that for air 1
n
1
= 1,0
1,0
and we can measure the angle of incidence, 1
θ
1
and the angle of refraction, 2
θ
2
. Then we can solve the equation for the unknown, 2
n
2
. To measure 1
θ
1
and 2
θ
2
, we need to draw the normal to the surface where the light ray enters the block. Use the protractor to measure an angle of 90
90
°
°
to the entry surface and draw the normal. Now use the protractor to measure 1
θ
1
and 2
θ
2
.
Enter the values you measured into a table which looks like the one below and calculate the resulting value for 2
n
2
.