Resonance Review

UC Irvine

Hoot_Tubes.mov

 

 

 

Bubbles
1st, 2nd, 3rd Harmonic
 (B. Barrett)

 

 

 

IV. Light (electromagnetic waves)

 

A. Speed

 

 

1.  3 x 108 m/s = c (in vacuum)

(fastest speed in universe)

In air v ≈ 3 x 108 m/s

 

 



Did you know that
 light can travel
 about 7.5 times around the world
 in 1 second!

 

v = fλ

 

c = fλ 

 

3 x 108 m/s = fλ

 

Divide both sides by λ

 

 

f = c/λ

 

Frequency, Wavelength

Relationship?

 

 

 

 

Inverse

 

 

 



 

 

 

 

 

Ex) What is the wavelength of light with a frequency of 7.69 x 1014 Hz in a vacuum?

c = fλ

 

3 x 108 m/s = 7.69 x 1014  Hz λ

 

 

 

 

λ = 4 x 10-7 m

 

 

 

2. Speed of light depends on medium

 

 

 

B. Reflection

| Larger Version |

 

 

Reflection
St. Mary's Physics

 

 

1. Law of Reflection

a.  θ of incidence = θ of reflection

 

 

 

 

θ of Incidence = θ of Reflection
St. Mary's Physics

 

 

 

 

Use the acute angles on your protractor 

Charles William Weick Elementary Mechanical Drawing, Theory and Practice
(New York: McGraw-Hill Book Company, 1915) 21

ETC Clipart  | Protractor

Line going through O, we will
 refer to as the baseline 

 

 

θin = θincidence
(angle incoming normal ray
 makes with the normal)

θref = θreflect
(angle reflected light makes with the normal)

 

 

 

 

 

 

 

Remember ...


... reflection always makes a V

 

 

 

What is the smallest mirror
you need to see your whole body?

 

 

 

1/2 your height

 

 

Click and drag gecko

 

 

 

 

 

 

Half the size
of the person

 

 

 

 

 

The image from a plane mirror:

 

a. Virtual (realistic) & Upright (Straight up and down)

 

 

 

 

 

 

 

 

b. Incident ray, normal line, and reflected rays are all in the same plane

 

Source: Elroy M. Avery School Physics (New York: Sheldon and Company, 1895) 77 

Clipart ETC

 

c. The distance the object is in front of the mirror equals the distance the image is behind the mirror

 

 

2. Two Basic Kinds of Reflection


a. Regular Reflection – reflection off a polished surface (produces images)

 

Regular Reflection Produces Images

http://www.freeimages.co.uk/

 

b. Diffuse Reflection – reflection off an irregular surface causing light to scatter (no image)




 

 

 

 

 

Which letter correctly

shows reflection?

 

 

 

 

 

 

 

Ray C

 

 

 

 

Angle of Reflection?

 

 

June 2009

 

 

 

 

 

 

60 degrees
(Angle from normal)

 

 

 

 

 

 

 

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