1. Tuesday(03/16): Ch.25 - Reflection of Light. Image Formation

by Plane and Curved Mirrors. HW: Read and Study pages 751-68, then

solve problems 6, 12, 16, 18, and 20 on page 770.

2. Wednesday(03/17): Ch.26 - Refraction of Light: Lens and Image

Formation. Index of Refraction, Snell's Law, and Total Internal Reflection.

HW: Read and Study pages 774-84 and pages 787-96 then solve

problems 2, 6, 10, 14 24, 38, and 50(a) on pages 812-14.

3. Thursday(03/18): Lab on Convex Lenses. HW: Process lab data and

begin to write abstract (due Monday).

4. Friday(03/19): Ch.27 - Diffraction, Interference and the Wave

Nature of Light. Young's Experiments and Thin-Film Interference.

HW: Read and Study pages 821-30, then solve problems 2 and 10 on

page 850. Read and Study pages 831-48, then solve problems 20 and

38 on pages 851-2.

5. Monday(03/22): Review I Chapters 24-25-26. Complete Review

Handout. HW: Complete Review Handout started in class.

6. Tuesday(03/23): Review II Chapters 24-25-26. Complete Review

Handout. HW: Complete Review Handout started in class.

7. Wednesday(03/24): Test on Chap. 25-26-27.  HW: Have a Safe

and Restful Spring Break. Go to website and study notes, graphics,

and links for Ch.29 - Particles and Waves.

Best to send an email to rpersin@fau.edu.

1. Light is electromagnetic radiation that consists of oscillating electric

and magnetic fields with different wavelengths; it is also capable of

stimulating the retina of the eye.

2. Light, moving through a vacuum, a travels in a straight line at a

speed c = 3.0 x 10⁸ m/s, and possesses the properties of both waves

and particles.

Reflection of Light:

3. The Law of Reflection Of Light states that the angle of incidence is

equal to the angle of reflection, θ_i = θ_r. Recall that both are measured

relative to the normal.

4. The flat mirrors form virtual images that are the same distance

behind the mirror as the object is in front. Flat mirror images are also

the same size as the object, but are reversed from left to right.

5. Curved mirrors that we will study are either concave, or convex.

They are both "spherical-parabolic." This means that they have some

properties of both a sphere and a parabola.

6. In particular, these mirrors have a radius of curvature, r, and a focal

point, f. The focal length is half the radius of curvature, f = ½r.

7. The mirror equation ( 1/d_o+1/d_i = 1/f ) relates object distance d_o,

image distance d_i, and focal length f of a spherical-parabolic mirror.

8. The magnification equation ( M = h_i/h_o = -d_i/d_o ) relates image height

and distance to object height and distance. All distances measured

behind a mirror are negative. In front, they are positive.

9.The convex mirror has only one case of image formation. For an object

placed at any distance in front of the mirror, the image is virtual (behind

the mirror), smaller, and erect (upright, not inverted).

10. A concave mirror has 6 cases of image formation, all dependent on

where the object is located relative to the front of the mirror.

Refraction of Light:

11. Refraction is the bending of light rays at the boundary between two

media. Refraction occurs only when the incident ray strikes the boundary

at an angle.

12. Snell’s law states that when light goes from a medium with an index

n₁ to another medium with an index n₂, it is bent relative to the normal.

The equation is n₁·sin i = n₂·sin r .

13. Light going from materials with a large n to those with a small n is

bent away from the normal. Some typical indices of refraction are:

vacuum, n = 1.00; air, n = 1.0003; water, n = 1.33. (See page 774.)

14. As a light ray travels from one medium into another medium it

changes speed and the light ray will change its direction unless it

travels along the normal. For the speed change, v = c/n.

15. Total internal reflection can occur if light travels from a medium with

a larger index of refraction, to one with a smaller index of refraction.

If the angle of incidence is greater than the critical angle, the light is

total internally reflected (fiber optics). The equation is sinθ_crit = n₂/n₁.

16. Light waves of different wavelengths have slightly different refractive

indices. Thus they are refracted at different angles. Light falling on a

prism is dispersed into a spectrum of colors.

17. Some materials, calcite for example, exhibit double refraction. This

means that one incident ray of light produces two refracted ones.

18. Mirages and the visibility of the sun after it has physically set are

natural phenomena that can be attributed to refraction of light in Earth’s

atmosphere.

19. A lens is a thin piece of glass that refracts, bends, light. The

different types of lenses are, double concave, double convex, plano-

concave, plano-convex, and convex-o-concave.

20. The location of an image created by a lens can be found using either

a ray diagram or the thin-lens equations, which are the same as the

mirror equations, 1/d_o+1/d_i = 1/f  and  M = h_i/h_o = -d_i/d_{o .}

21. The image produced by a converging lens is real and inverted when

the object is outside the focal point and virtual and upright when the

object is inside the focal point. Diverging lenses always produce upright,

virtual images.

22. We will study double convex (convex), and double concave (concave)

lenses in detail because they have the most applications.

23. For the concave lens, there is only one case of image formation. But

for the convex, we have 6 cases all based on where the object is located.

Diffraction and Interference of Light:

24. Light passing through a narrow hole or slit is diffracted, or bent from

a straight-line path. Light waves with the same wavelength and constant

phase differences interfere with each other to produce light and dark

interference patterns.

25. Interference between light diffracted from two closely-spaced narrow

slits causes an interference pattern to appear on a distant screen.

26. The wavelength of light can be measured by analyzing the double-slit

interference pattern. The equation is λ = xd/L .

27. In double-slit interference, the position of a bright fringe requires the

path difference between two interfering point sources to equal a whole

number of wavelengths.

28. Single slits produce diffraction patterns that are less well defined than

those formed by double slits. The equation is λ = yw/L .

29. In double-slit interference, the position of a dark fringe requires the

path difference between two interfering point sources to equal an odd

number of half-wavelengths.

30. Diffraction gratings with large numbers of evenly-spaced slits

produce interference patterns that are used to measure the wavelength

of light precisely. The equation is λ = dsinθ_n/n .

31. Light waves form a diffraction pattern by passing around an obstacle

or bending through a slit and interfering with each other.

32. Diffraction limits the resolving power of lenses.

33. The position of a maximum in a pattern created by a diffraction grating

depends on the separation of the slits in the grating, the order of the

maximum, and the wavelength of the light.

34. Colors in soap and oil films are caused by the interference of specific

colors of light reflected from the front and back surfaces of the thin film.

This occurs at odd multiples of λ/4 .

35. And still, we need these steps to solve any problem in Physics:

(i) read the problem and identify the given variables

(ii) determine what you are asked to solve for

(iii) find the correct equation to use

(iv) use Algebra, Trigonometry, and/or Calculus to isolate the unknown

(v) substitute-in the given information and simplify.