Question

100 POINTS

1. Based on Part 1, how does the angle of incidence relate to the angle of reflection? Explain it using your data. Write a statement or law of reflection describing this relationship.

(Score for Question 2: ___ of 10 points)
2. What value did you calculate for the index of refraction of the block in Part 2? How does your value compare to the accepted value of 1.50? Calculate the percentage error. Different materials have distinct indexes of refraction. Explain how you might identify a material based on experiments like this one. Mention at least one of the difficulties in identifying materials based on their indexes of refraction.

(Score for Question 3: ___ of 5 points)
3. Light coming from a fish makes an incidence angle of 30° to normal under the water. The index of refraction of water is 1.33. A fisherman is looking at the fish through air. At what angle with the normal will the fish appear to the fisherman? Use Snell’s law:

Answer 1

Question 1:

The angle of incidence is the angle between the incident ray and the normal to the surface.

The angle of reflection is the angle between the reflected ray and the normal to the surface.

The law of reflection states that the angle of incidence is equal to the angle of reflection. This means that the two angles are always the same.

This can be explained using the following diagram: Attachment

• The normal is a line perpendicular to the surface.
• The angle of incidence is the angle between the incident ray and the normal.
• The angle of reflection is the angle between the reflected ray and the normal.

Additional:

The law of reflection is a fundamental law of optics. It is used in many applications, such as mirrors, telescopes, and cameras.

`\hrulefill`

Question 2: ___ of 10 point

The index of refraction formula is calculated using formula:

`\boxed{\tt n =( c )/(v)}`

where:

• n is the index of refraction
• c is the speed of light in a vacuum
• v is the speed of light in the medium

The index of refraction is a dimensionless quantity, which means that it does not have any units. It is a ratio of the speed of light in a vacuum to the speed of light in a medium.

Now,

The accepted value of the index of refraction for ordinary window glass is 1.50.

My calculated value of the index of refraction for the block was 1.32.

The percentage error is calculated as follows:

Percentage error = (accepted value - calculated value) / accepted value * 100%

= (1.50 - 1.32) / 1.50 * 100% = 12%

Therefore, my calculated value is 12% lower than the accepted value. This is within the acceptable range for this type of experiment.

Some of the ways you can identify a material based on its index of refraction:

• Compare the index of refraction of the material to known values.
• Use a spectrometer to measure the spectrum of light that is refracted by the material
• Use a microscope to examine the material for features that are characteristic of specific materials.

One difficulty in identifying materials based on their indexes of refraction is :

• the index of refraction can vary depending on the wavelength of light that is used. This means that you need to use light of a specific wavelength when you are doing your experiments.

`\hrulefill`

Question 3.

Note:

Snell's law states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the refractive indices of the two media.

Given:

• Angle of incidence (θ1) = 30°
• Index of refraction of water (n2) = 1.33
• Index of refraction of air (n1) = 1

To find:

* Angle of refraction (θ2)

Using Snell's law, we have:

`\tt (sin \theta 1 )/(sin \theta2 )= (n1 )/(n2)`

`\tt (sin 30)/(sin \theta2 )= (1 )/(1.33)`

sin θ2 = sin 30* 1.33

sin θ2 = 0.5*1.33

sin θ2 = 0.665

θ2 =
`\tt sin^(-1)(0.665) = 41.8`

Therefore, the fish will appear to the fisherman at an angle of 41.8° with the normal.