Why can't we say two current carrying wires are attracted or repelled to each other due to an electrical force?

To find the magnetic field created by current carrying wires, explain how you use the right hand rule. (In other words, explain what direction your thumb points, and what your fingers mean). Include a drawing.

Where else have we used the right-hand rule? Explain two situations.

Why would a compass not work properly in an electrical storm?

2. Electro-magetic waves are a result of what?

Describe how the electric field and magnetic field are related in an EM wave. Draw a picture to help your explanation.

As you move from left to right on the EM spectrum, what happens to the wavelength of the EM waves?

As you move from left to right on the EM spectrum, what happens to the frequency of the EM waves?

What must be true in order for the last two answers to be true?

What is the only thing that distinguishes a long radio wave from an X-ray?

Why are X-rays so dangerous when radio waves are harmless if they are made of the exact same thing?

List the following waves in order from longest wavelength to shortest wavelength: X-rays, Green, Ultraviolet, Microwaves, and Infrared.

If you listed the same waves from above in order from smallest frequency to highest frequency, how would that list compare to the one you just made?

3. What is the frequency of the color yellow, which has a wavelength of 620 nm? (4.8(10^14 Hz)

What does that mean?

Find the wavelength of the EM wave that has a frequency of 1.2(10^17) Hz. (2.5 nm)

Where does that EM wave fall in the spectrum?

4. Define Refraction:

Why does light bend when it goes from one medium to another that has a different index of refraction?

Why does light slow down when it goes from one medium to another that has a different index of refraction?

Does light always slow down when going from one medium to another? If not, what would have to be true in order for it to speed up from medium to another?

5. Explain the index of refraction and how it relates to the bending of the light:

What happens to the index of refraction (which is n) as the speed of light in the medium gets smaller?

What relationship does n have with the speed of light in the medium?

Does light always slow down when it goes from one medium to another? If not, what must true in order that it actually speeds up?

Derive Snell's Law from the following diagram:

If light went from water to glass, would it speed up or slow down? Explain why.

If light went from diamond to water, would it speed up or slow down? Explain why.

6. Find the angle the light enters the glass that has an index of 1.65, when the angle of incidence is 45 degrees, and Show that the angle the light leaves the glass is equal to the angle of incidence. (25.4 degrees; 45 degrees)

Find the angle the light enters the water container when it has to go through glass first, when the angle of incidence on the glass plate is 40 degrees. (28.9 degrees)

Do you think when the light exits the water container it will have the same angle that it did when it entered the glass plate? Why or why not?

Find the exit angle out of the water to confirm your answer.

For the following picture, draw how the light wave would travel through this piece of glass, if it had an index of refraction of one.

7. Explain why when white light enters a glass prism, it creates a rainbow.

Which color has the largest index of refraction for a given prism?

Which color has the smallest index of refraction for a given prism?

Find the angle of the emitted rainbow if white light enters a prism parallel to the base of a prism with an apex angle of 60°. Do this by finding the exit angle of red (700-nm) and violet (400-nm). The index for red is 1.50 and the index for violet is 1.52. (6.2 degrees).

What happens to the angle between the two ends of the spectrum (red and violet) as the difference between their index of refractions increases? Explain

8. When viewing a rainbow, which color is on top and which one is on bottom?

Why can't one ever truly reach the end of a rainbow?

9. Why is our sky predominantly blue? (consider the sizes of the particles that make our atmosphere)

If another planet's sky was predominantly red, what would that mean about the particles in its atmosphere?

If another planet's sky had predominantly mediumed sized particles, what would that sky look like?

What if another planet's atmosphere had an even mixture of small, medium, and large particles? What would it look like?

What would that compare to our planet?

10. Explain why sunsets are predominatly reds, pinks, and oranges.

Which color would be the last to be filtered out by the atmosphere? Explain.

Apply the knowledge of a sunset and explain why some clouds are actually greenish (in storms typically with hail).

11. What are you actually seeing when driving on a hot road, and it appears to be water on that road ahead?

Why does it always disappear when you get a certain distance to it? (don't just say because it isn't really water either! Consider angle of the waves)

What causes the index of fraction of air to change?

Given an example where the index is constantly changing, causing a wavy background.

12. What causes sound to refract over lake water, which allows one to hear things from the other shore easily?

What would have to be true in order for there not to be any refraction?

How is this similar to the mirage on the road example?

How is it different? (Other than one is light and the other is sound)

13. Give one practical example of where polarization of light is used almost everyday.

If light reflecting off of the road is primarily horizontal when it shines in your eyes while driving, how should your sunglasses be polarized to help eliminate the glare? (Circle the appropriate plate).

Due to this principle, if a wave hits two small slits, what comes out the other side?

Is there a limit to how many "new" waves can occurr? Give an example that proves your answer.

15. In order for diffraction to occur, how does the size of the slits have to compare to the wavelength of the wave?

When you drive your car through a concrete tunnel the AM stations always go static while the FM stations stay clear. Explain why this is so.

16. When monochromatic light (one color) hits two small slits, an interference pattern emerges on the screen as a series of bright and dark fringes. What is the main reason for this pattern?

What must be true about the path difference in order that a bright fringe occurs on the screen? (The two waves arrive in phase)

What must be true about the path difference in order that a dark fringe occurs on the screen? (The two waves arrive out of phase)

Sometimes the two waves meet at the screen 90 degrees out of phase, and only partially cancel. What consequence does that have on how precise the bright fringe stops and the dark fringe begins?

17. A monochromatic light beam hits two slits with a .50-mm separation. The screen is 1.5 meters away and the distance between the central bright line and the next bright line is 1.95-mm. Find the wavelength of the light beam. (650 nm)

A laser light (red at 700 nm) is shown on a double slit. The screen is 2.0 meters away, and the first bright fringe is .80 mm from the central bright fringe. What is the distance between the slits? (d = .00175 m)

Two parallel slits .12-mm apart are illuminated by light of wavelength 500-nm. A viewing screen is 1.5-m from the slits. How far from the central bright line is the second bright line? (y =.0125 m)

How far is the first dark line? (y = .0094 m)

How far is the fifth dark line? (y = .028 m)

As the slit separation gets smaller (d), what happens to the distance between the central bright fringe and subsequent bright fringes (Y)?

What relationship does slit separation (d) have with distance between fringes (y)?

If the slit distance starts at .005 mm, and then changes to .010 mm, by how much will the distance between the fringes change? (reduce by a half) Show why!

As the distance from the screen increases (L), what happens to the distance between the central bright fringe and subsequent bright fringes (Y)?

What relationship does the distance between the screen and slits (L) have with distance between fringes (y)?

If the distance between the screens starts at 1.0 meter and changes to half a meter, how will the distance between the fringes change? (reduce by a half) Show why!

18. Which color is bent more through diffraction: red or violet?

White light is shone on a grating ruled with 10,000 lines/cm. Find the angular width of the first-order spectrum.

Given the picture below, consider the path difference s, and explain why the color red would need to have a larger y (meaning it would be farther up the screen on the picture) as compared to violet. (Consider their wavelengths).

Why would having more slits, such as in diffraction grating, which can have thousands of slits per inch, cause the bright fringes to spread farther apart? (Consider the number of new waves created)

19. If you shine a monochromatic light through a single slit, and you want wide bright fringes on the screen, should your slit width be small or wide?

What relationship would you say slit width has with the width of the bright fringes?

20. Why are you able to hear someone coming around a corner in a hallway?

Consider a room with a single door, and the room is completely dark and the door is cracked. If the light in the hall is on and someone is standing in the hall outside the door and you are standing in the corner as shown in the picture, would light reach your corner?

Explain why one wave would make it to the corner and the other wouldn't

21. When light enters a soap bubble, there are two things that contribute to the canceling of some of the colors. What are they?

If soap bubbles only had one layer, would they still exhibit the interference patterns that result in the rainbow colors?

Explain why.

22. Why do objects appear closer to the surface of water than they actually are?

If you are trying to spear a fish and you are standing in a boat, how would you have to throw the spear in order to accomplish that?

You are trying to grab a fish out of a barrel (An exercise in quickness). The fish appears to be .45 meters from the top of the water. If you grab .45 meters into the water and grasp, will you grab the fish?

How deep actually is the fish? Assume the index of the water is 1.35. (.61 meters)

As the index of refraction of the water increases, what happens to actual depth of the object? In other words, does it get farther or closer to the depth it appears to be?

As the index of refraction of the water increases, what happens to the cone of sight? Does it increase or decrease? What does that mean?

23. Why do objects appear the same distance inside a plane (flat) mirror as it is located on the outside?

In order for a surface to be smooth to a particular wave, what must be true about its smoothness, which means the distance between its bumps and irregularites?

Explain why a chain linked fence would be considered smooth for long radio waves?

Why isn't it smooth to most of the waves on the EM spectrum?

Explain why surfaces that reflect visible light have to be extremely smooth (i.e. extremely small distances between the bumps and irregularites).

24. What kind of mirror gives a virtual upright image?

What makes an image virtual as opposed to real? Explain how both types of images are made.

What are the two rules for drawing the ray diagrams for a convex mirror?

1. Light that hits the mirror parrallel to the horizontal, they reflect:

2. Light that hits the mirror such that it can be traced through the center of the circle reflect:

Draw in the necessary light ray lines to show where the image would be located for the convex mirror.

25. A candle 6-cm high is placed 30-cm in front of a convex mirror whose focal length is 30-cm. Find the position, size, and nature of the image. (i = -15 cm virtual; m = .5 times smaller upright)

Can a convex mirror give any other type of image?

Your face is 10-cm from a convex mirror, and your image appears to be 5-cm inside the mirror. What is the focal length of that mirror? (-10-cm)

How does your image size compare to your actual size? In other words, what is the magnification? (m = .5, which means half the size).

Summarize what must be true between the object distance and focal length of a convex mirror for the image to be exactly half the size of the object.

The magnification for a particular convex mirror is .60. If the image is 15-cm inside the mirror, what is the focal length of the mirror? (-37.5 cm)

Show algebraically that the focal length of any mirror can be written as:

Prove that the magnification for a convex mirror will always be less than one. In order to do this consider that the sum 1/b + 1/i must always be less than one, because the focal length of a convex mirror is always negative. From there, set up an inequality, solve for b and apply that to the magnification equation. (If you are unclear, get help from me).

26. In what ways is a concave mirror different from a convex mirror? (You should have two ways cited).

1.

2.

What are the three rules for drawing ray diagrams for concave mirrors?

1. When light hits the mirror parrallel to the horizontal it reflects:

2. When light hits the mirror such that it can be traced through the center it reflects:

3. If light goes through the focal point and hits the mirror it relfects:

Draw in the necessary light ray lines to show where the image would be located for the following concave mirrors:

Summarize how the image size and position changes as the object moves from inside the focal point to outside the center of the circle:

Where must the object be in order for the image size to be the same as the object size, which means the magnification equals one (technically -1.0 because it is inverted)?

Prove that situation, that if the object is located at the center of the circle, the image will be located at C, and that the magnification will equal -1.0. In order to do this, use the mirror equation: 1/b + 1/i = 1/f, and consider the fact that f = R/2, which means C = 2f (C is the distance from the mirror to the center of the circle, which means it is the radius). If you are unclear on what to do, see me.

Show that when the object is located at f, the image doesn't exist. (In this case, the image distance, i, would be considered infinity, since the lines never intersect, and 1/infinity is equal to zero).

27. A candle is placed 5-cm in front of a concave mirror with a focal length of 15-cm. Find the position, size, and nature of the image. (i = -7.5 cm virtual; m = 1.5 times bigger upright)

A candle is placed 20-cm in front of the same concave mirror. Find the position, size, and nature of the image. (i = 60 cm real; m = - 3 times bigger inverted)

A candle is placed 35-cm in front of the concave mirror. Find the position, size, and nature of the image. (i = 26.25 cm real; m = .75 inverted)

Connect the last three problems with their appropriate ray diagrams found in problem 25.

Show that when an object is considered an infinite distance away, the image is located at the focal length. (Remember: 1/infinity equals zero).

28. Explain the difference between a converging lens and a diverging lens.

What type of lens (concave or convex) is a converging lens?

What type of lens is a diverging lens?

How is a concave lens similar to a concave mirror? How are they different? (You should have one similarity and one difference).

1.

2.

How is a convex lens similar to a convex mirror? How are they different? (You should have one similarity and one difference).

1.

2.

29. What kind of lens gives a virtual upright image?

What are the two rules for drawing ray diagrams for concave lens?

1. When light hits the lens parrallel to the horizontal it bends such that:

2. When light travels through the middle of the lens, it:

Draw the ray diagram for the concave lens below:

30. A movie director uses a concave lens of focal length 60-cm to view a scene of the movie. Where does the image of the scene 30 meters away seem to be located, and how much smaller is it?? (-59 cm; 1/51 the size)

Can a concave lens give any other type of image?

The movie scene is 1.0 meters (which is 100 cm) away, and the scene appears to be 50 cm inside the lens. What is the focal length? (-100 cm)

How does your image size compare to your actual size? In other words, what is the magnification? (m = .5, which means half the size).

Summarize what must be true between the object distance and focal length of a concave lens for the image to be exactly half the size of the object.

Is that the same thing you found for the convex mirror, or is it different?

The magnification for a particular concave lens is .05. If the image is 25-cm inside the mirror, what is the focal length of the mirror? (-26 cm)

You did this same proof for the convex mirror in problem 25 level 8. If you received help to solve it, try doing it again without looking at your solution to see if you can do it on your own. If you skipped that problem, and have not received help, then I advise you to do so as soon as possible!
Prove that the magnification for a concave lens will always be less than one.

Show that if the object is considered an infinite distance away (meaning its distance is considerably larger than the focal length), the image will appear the same distance as the focal length. (See problem 27 level 5 for the hint).

31. In what ways is a concave mirror different from a convex mirror? (You should have two ways cited).

1.

2.

What are the three rules for drawing ray diagrams for convex lens?

1. When light hits the lens parrallel to the horizontal it bends through:

2. When light travels through the middle of the lens it:

3. If light travels through the focal point first it bends:

Draw in the necessary light ray lines to show where the image would be located for the following convex lens:

Summarize how the image size and position changes as the object moves from inside the focal point to outside of 2f:

Where must the object be in order for the image size to be the same as the object size, which means the magnification equals one (technically -1.0 because it is inverted)?

Is that the same place compared to the concave mirror? (Remember c = 2f).

You did this same proof for the convex mirror in problem 25. If you received help to solve it, try doing it again without looking at your solution to see if you can do it on your own. If you skipped that problem, and have not received help, then I advise you to do so as soon as possible!
Prove that situation, that if the object is located at 2f, the image will be located at 2f, and that the magnification will equal -1.0.

Show that when the object is located at f, the image doesn't exist.

32. A candle is placed 5-cm in front of a convex lens with a focal length of 10-cm. Find the position, size, and nature of the image. (i = -10 cm virtual; m = 2.0 times bigger; upright)

A candle is placed 15-cm in front of the same convex lens. Find the position, size, and nature of the image. (i = 30 cm real; m = - 2.0 times bigger inverted)

A candle is placed 25-cm in front of the same convex lens. Find the position, size, and nature of the image. (i = 16.7 cm real; m = 2/3 the size inverted)

Connect the last three problems with their appropriate ray diagrams found in problem 30.

Show that when an object is considered an infinite distance away, the image is located at the focal length.

33. A myopic eye has a far point of 15-cm. Find the power of the lens in diopters of the corrective lens. (-6.67 D)

A hyperopic eye has a near point of 100-cm. Find the power of the lens in diopters of the corrective lens so that the person can see at 50 cm. (1 D)

A myopic person whose eyes have far points of 60-cm is lent a pair of glasses whose power is –1.5 D. How far can she clearly see with the glasses? (b = 6 m)

A hyperopic eye has a near point of 60-cm. What is its near point when a correcting lens of +3.33 D is used? (b = .20 m)