Lab 5, Reflection and Refraction

Lab 5 of PHYS 2C LAB
Reflection and Refraction
Section 1:
You may give me a graph showing both "left" (positive) and "right" (negative) data. Or giving me two graphs will be fine with me as well.

Incident Angle, q _i Unit: ( )	Reflected Angle, q _r (Left, "+") Unit: ( )	Incident Angle, q _i Unit: ( )	Reflected Angle, q _r (Right, "-" ) Unit: ( )
0.0		-0.0
10.0		-10.0
20.0		-20.0
30.0		-30.0
40.0		-40.0
50.0		-50.0
60.0		-60.0
70.0		-70.0
80.0		-80.0

Question 1

Do the two sets of measurements (incidence on opposite sides of the normal) agree? If not, why?

What is the accuracy of this test of the reflection?

Requirement:

Graph "q _reflected versus q_incident" from air into the acrylic	y - Intercept, unit: N.A.	Slope, unit: N.A.	Regression Coefficient
Theoretical	0 ?	1 ?	1
Measured
%error	N.A.	%	%

According to the law of reflection, what is the physical meaning of the B-intercept here?

Never just write something like: " They agree very well." Or you will lose 1 point.

Section 2:
Skip the work concerning n₁q ₁ =n₂q ₂

And give me two graphs.

Question 2-1

Plot the data as "sinq ₂ versus sinq ₁". Does this graph support Snell's Law?

What is the index of refraction of the cylindrical lens?

Requirement:

Graph "sinq ₂ versus sinq ₁" from air into the acrylic
Incident Angle, air, q ₁, Unit: ( )	0	10	20	30	40	50	60	70
Refracted Angle, the acrylic, q ₂, Unit: ( )

Graph "sinq ₂ versus sinq₁" from air into the acrylic	y - Intercept, unit: N.A.	Slope, unit: N.A.	Regression Coefficient
Theoretical	0 ?	n _acrylic or n _acrylic^{- 1} ?	1
Measured
%error	N. A.	N. A.	%

Graph "sinq ₂ versus sinq ₁" from the acrylic into air
Incident Angle, the acrylic, q ₁, Unit: ( )	0	5	10	15	20	25	30	35	40
Refracted Angle, air, q ₂, Unit: ( )

Graph "sinq ₂ versus sinq₁" from acrylic into air	y - Intercept, unit: N.A.	Slope, unit: N.A.	Regression Coefficient
Theoretical	0 ?	n _acrylic or n _acrylic^{- 1} ?	1
Measured
%error	N. A.	N. A.	%

(0.5 POINT) You must use M (Slope), B (Intercept), and R (Regression Coefficient) on your two graphs "sin q ₂ versus sin q ₁" to answer this question.

(0.5 POINT) And write down the average of your measured n _acrylic .

Don't just write something like: "It supports very well." Or you will lose 1 point.

Section 3
All you have to do here is to observe the phenomena.

No graph is required.
Question 3-1

At what angle of refraction do you begin to notice the colors separating?

At what angle of refraction is the separation of colors a maximum?

What colors do you see? Write them in order of increasing angle of refraction.

Requirement:

All you have to do is to fill out the following table.

DATA TABLE	Colors (Red or Blue, etc.)	Incident Angle, q _i, Unit: ( )	Refracted Angle, q _r, Unit: ( )
Beginning of Color Ray
Brightest of Color Ray

Skip the work that the index of refraction of the acrylic cylindrical lens depends on wavelength.

Section 4
Question 4-1

Do you see reflected ray from the flat surface of the lens? Answer Yes or No.

Question 4-2

Is there a reflected ray for all angles of incidence? Answer Yes or No.

Question 4-3

Are the angles of the reflected ray consistent with the law of reflection? Answer Yes or No.

Question 4-4

How does the intensity of the reflected ray vary with the angle of incidence? (0.5 POINT)

Requirement:

Does it get brighter or darker as the angle of incidence increases? Is there any sudden jump in Brightness? At what angle of incidence does it jump?

Question 4-5

At what angle of incidence is all the light reflected? It means no refracted ray. (0.5 POINT)

Requirement:

It is the definition of "the critical angle."

Question 4-6

Determine the index of refraction of the acrylic cylindrical lens. (0.5 POINT)

Requirement:

Using Snell's Law with n of air is 1 and the definition of "the critical angle," you must give a mathematical equation between the critical Angle, q _c, and the index of refraction, n.

Calculate the %Difference between the index of refraction here and one from Section 2.

Direction	Question 4-5 Critical Angle q _c, Unit: ( )	Question 4-6 The index of refraction, n from the critical Angle q _c, Unit: ( )	The index of refraction, n_acrylic from Section 2	Question 4-6 %Difference (0.5 POINT)
From the acrylic into air

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