Experiment 1: Color Addition



Ronnel Fernandez

4th period

12-1-08

Experiment 1: Color Addition

Part 1

Procedure

|Colors Added |Resulting Color |

|Red + blue + green |white |

|Red + blue |Pinkish purple |

|Red + green |orange |

|Green + blue |cyan |

Questions

1. Is mixing colored light the same as mixing colored paint? Explain.

2. White light is said to be the

Part 2

1. Trial 1: Arvin

|Color of Light |Line |Apparent Color of Ink |Do they look different? |Actual Color of Ink |

|Blue Light |A |Dark violet |yes |red |

| |B |Dark blue | |Black |

|Red Light |C |orange |yes | |

| |D |maroon | | |

2. Trial 2: Ronnel

|Color of Light |Line |Apparent Color of Ink |Do they look different? |Actual Color of Ink |

|Blue Light |A |Black |yes |Red |

| |B |blue | |black |

|Red Light |C |orange |yes |red |

| |D |black | |black |

3. Look at red and black lines under red light. Which line is easier to see?

The red line is easier to see.

Experiment 2: Prism

Snell’s Law n1sinθ1 = n2sinθ2

3. Rotate the trapezoid until the angle (θ) of the emerging ray is as large as possible and

the ray separates into colors.

a. What colors do you see? In what order are they?

Colors we see= white light and a rainbow…roygbiv. The order they’re in is random.

b. Which color is refracted at the largest angle?

All colors.

4. Without repositioning the light source, turn the wheel to select the three primary color rays. The colored rays should enter trapezoid at the same angle that the white ray did. Do the colored rays emerge from the trapezoid parallel to each other? Why or why not?

Yes they are parallel because the sides of the 3D trapezoid all have equal measurements in both sides.

Experiment 3: Reflection

Part 1: Plane Mirror

Table 3.1: Plane Mirror Results

|Angle of Incidence |Angle of Reflection |

|20° |21° |

|42° |34° |

|60° |50° |

1. What is the relationship between the angles of incidence and reflection?

Angle of incidence is greater than the angle of reflection.

2. Are the three colored rays reversed left-to-right by the plane mirror?

yes

Part 2: Cylindrical Mirrors

Table 3.2: Cylindrical Mirror Results

| |Concave Mirror |Convex Mirror |

|Focal Length |6 cm |1 cm |

|Radius of Curvature |40° |40° |

|(determined using compass) | | |

1. What is the relationship between the focal length of a cylindrical mirror and its radius of curvature? Do your results confirm your answer?

2. What is the radius of curvature of a plane mirror?

45 degrees

Experiment 4: Snell’s Law

Snell’s Law:n1sinθ1 = n2sinθ2

Table 4.1: Data and Results

|Angle of Incidence |Angle of Refraction |Calculated Index of refraction of arcyllic |

|20 |25 |0.34 |

|30 |35 |0.5 |

|15 |35 |0.25 |

| | |Average: 11.58 |

Analysis

1. For each row of Table 4.1, use Snell’s Law to calculate the index of refraction, assuming the index of refraction of air is 1.0.

2. Average the three values of the index of refraction. Compare the average to the accepted value (n=1.5) by calculating the percent difference.

Question

What is the angle of the ray that leaves the trapezoid relative to the ray that enters it?

Experiment 5: Total Internal Reflection

Snell’s Law States:

Nsinθc = 1/sin90°

Solving for the sine of critical angle gives:

Sinθc = 1/n

5. . θc= 40° (experimental)

6. . θc = ? (theoretical)

7. Calculate the percent difference between the measured and theoretical values:

% difference =?

Questions

1. How does the brightness of the internally reflected ray change when the incident angle changes from less than θc to greater than θc?

2. Is the critical angle greater for red light or violet light? What does this tell you about the index of refraction?

Experiment 6: Convex and Concave Lenses

Procedure

Table 6.1 Results

| |Convex Lens |Concave Lens |

|Focal Length |13 cm |15 cm |

Question:

5. Are the outgoing rays converging, diverging or parallel? What does this tell you about the relationship between the focal lengths of these two lenses?

a. It’s converging and diverging

6. What is the effect of changing the distance between the lenses? What is the effect of reversing their position?

a. When the light first hits the convex mirror the lines go inward clashing together then hits the concave mirror then goes outward and makes a v shape.

Pictures:

Analysis:

Conclusion:

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