Reading Quiz

Light can be polarized because:

1. the waves are transverse waves.2. it is made up of waves.3. it contains a range of wave lengths.

Fig. 16.1

Fig. 16.14

Interference can be seen when the layer thickness is around the wavelength of light.

€

y =x

wλ

Single Slit, Dark Fringe

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y =x

d

λ

2Double Slit, Dark Fringe

Fig. 16.18

Interference can be seen from a single slit. Different points across the slit are sources of waves that can interfere at y.

Electromagnetic Waves

Looking down the x-axis at the electric field strength.

Polarizers have an axis of transmission

Reflected light or scatter light becomes Polarized after reflection or scattering

1. Cornea2. Iris3. Optic Nerve4. Retina5. Lens

Quiz 1: RetinaQuiz 2: IrisQuiz 3: There are how many types of light sensitive cells are in the eye?1 2 3 4 5

If the wheel has 100 slots and is turning at a rate of 100 times per second, when the light turns dark what is the speed of light?

Quiz 4

Visible Light has a wave length of approximately

1. 1/2 Microns

2. 1/2 Millimeter

3. 1/2 Centimeter

4. 1/2 Meter

5. 1/3 Kilometer

• Why is the shy blue?

1. Short wavelengths are scatter more from small particles than long wavelengths.

2. Long wave lengths are scatter more from small particles than short wavelengths.

3. Polarization effects due to dust in the sky

4. Subtractive color mixing

5. Additive Color Mixing

Quiz Question 1:

Compare sound waves with electromagnetic waves. Which of these statements is FALSE?

A. Electromagnetic waves travel faster than sound waves.

B. For both types, the wave velocity equals the wave length times the frequency (v=f).

C. Both sound and electromagnetic waves are transverse waves.

D. Electromagnetic waves can travel through vacuum, but sound waves cannot.

This demonstration showed how a changing magnetic field produced a changing electric field; further, a changing

electric field produces a changing magnetic field.

Fig. 16.2

A changing current in an antenna causes changing electric and magnetic fields.

Fig. 16.3

Speed of light c = 2.98 x 108 meters/sec

Light is an electromagnetic wave with changing electric and magnetic fields.

Example: Plane Wave

Fig. 16.4

A method for measuring the speed of light.

Fig. 16.5

Speed c = f

Visible Light: 380nm to 750nmnm=nanometers or10-9 m

White Light is a mixture of many wavelengths or colors

Retina is made of rods and conesCones give color vision, concentrated in the center called the foveaRods are distributed throughout the retina, night and peripheral vision.(no color vision0

• There are three types of color sensitive cones in the eye.

Additive Color mixing

• Selective absorption is a subtractive process.

The surface absorbs light of a given color

The light can be reflected In one of two ways

Mirror like All directions

Cyan, yellow, magenta

Fig. 16.12

Observation of interference effects with light.

Fig. 16.13

1. What happens if the path difference at the point y is half a wavelength?

2. What happens if the path difference at y is a full wavelength? Or 2? Or 3?

Question 2:

In a double slit interference experiment, what happens when the distance d between slits gets smaller?

A. The spots on the wall move closer together.

B. The spots move farther apart.

C. The spots don’t move, but become dimmer.

D. The spots don’t move, but become brighter.