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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

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

θin = θincidence (angle incoming normal ray  makes with the normal) θref = θreflect (angle reflected light makes with the normal)

Reflection always makes a V

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

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

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

Refraction