1. Lenses are used to make objects appear larger or smaller. List at least five different uses for a lens.

2. Large, curved mirrors are used to prevent shoplifting in retail stores. Explain why these mirrors are curved instead of flat.

3. A car mirror on the passenger-side door often has a sign that reads, “Objects in mirror are closer than they appear.” How does the shape of the mirror necessitate this warning?

Notebook # 9Bellringer – Section 4

I. Refraction of lightA. Refraction – bending of light.

1.When light travels from one medium to another, it:

a. changes speed.

Water

Air

B. Going from a higher speed to a lower speed:

1. Light bends toward the normal.

NORMAL

Water

Air

C. Going from a lower speed to a higher speed:

1. Light bends away from the normal.

NORMAL

D. Refraction of light creates a virtual image.1. Our brains “think” light travels in a straight

line when it is actually bending.

A. Total internal reflection –

1. Light is reflected as if were bouncing off of a mirror.

a. Optical fibers take advantage of total internal reflection to transmit data.

II. Total Internal Reflectionlight traveling from

one medium to another being completely reflected at the boundary.

b. Data is converted into digital signals consisting of pulses of light by lasers.

c. Multiple signals can be sent through one line using different λ.

III. LensesA. Lens – Transparent object that refracts light

waves such that they:

1. converge – come together.

2. diverge – move apart.

B. Converging Lens – bends light inward.

Thickerin the

middle

C. Diverging Lens – bends light outward.

Thinnerin the

middle

Notebook #10

Workbook:

Pages 63 & 64