Pulses, Reflections and Basic Interference

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ScienceHelpNow.com Period

Waves: Section 11-6

“Pulses, Reflections and Basic Interference”

1. What four things will we be discussing in this section?

2. Draw two different diagrams below which illustrate a “single pulse”

3. Draw a periodic wave in the space below.

4. Look up the word “periodic” on the Internet as it applies to science. ( Type in key words “definition periodic scientific” )

List two synonyms for the word “periodic” which apply well to our discussion of “periodic waves”

5. Look up the word “wave” on the Internet as it applies to science. ( Type in key words “definition wave scientific” )

6. Define “periodic wave” scientifically using the definitions you looked up and the information in the video.

7. The diagram below shows a pulse traveling to the right along a string toward a rigid wall, like a brick wall or the wall of a house. Draw a second diagram in the space below it to show that the pulse reflects back inverted as compared to its original orientation, and traveling in the opposite direction.

8. Draw vector arrows on the diagram above to show the direction of the velocity of the original pulse and the reflected pulse.

9. What would be a simple synonym for the word “inverted” ? ______

10. The diagram below shows a pulse traveling to the right along a rope toward a less dense piece of string. Draw a second diagram in the space below it to show that the pulse both reflects back in the same orientation and is transmitted to the lighter string, also in the same orientation (on top)

11. SUMMARY : When a wave encounters a boundary (a different material) it can be

re ______, tr______or absorbed (a different video) .

And, when a wave

encounters a more dense or more rigid medium, it reflects back and is ______.

When a wave encounters a less dense medium, it reflects back with the same ori______

and continues on at a different ______.

12. The medium (substance the wave is traveling through) determines the ______

of the wave. When a wave moves into a different substance, its speed ______.

13. The wave shown below is a ( transverse , longitudinal ) wave. It could be a

( light , sound ) wave. The vector arrow shows that this wave is traveling to the ( right , left ).

Point A will vibrate ( up and down , left to right ) as the wave passes by. This means that Point A ( which

is a particle along the wave path) vibrates or oscillates ( perpendicular , parallel ) to the direction of

motion.

14. The box on the right shows a vector arrow oriented

from left to right. Draw a double arrow perpendicular to

the arrow in the box to show how the points on a transverse

wave oscillate

15. Describe ( up, down etc… ) how Point A will move as the wave passes it. The wave is traveling to the right.

______

16. Describe ( up, down etc… ) how Point A will move as the wave passes it. The wave is traveling to the left.

______

17. HERE’S ONE MORE DIFFERENT WAY TO SHOW THE QUESTION.

Describe ( up, down etc… ) how Point A will move as the wave passes it. The wave is traveling to the right.

______

18. For each question above (13-15) how would you describe the displacement of Point A from before the

wave passes Point A until after the wave passes Point A ? The displacement is ______because A ends up back

where it started.

19. The wave shown below is a ( transverse , longitudinal ) wave. It could be a

( light , sound ) wave. The vector arrow shows that this wave is traveling to the ( right , left ).

Point A will vibrate ( up and down , left to right ) as the wave passes by. This means that Point A ( which

is a particle along the wave path) vibrates or oscillates ( perpendicular , parallel ) to the direction of

motion.

I I I I I I I I I I I I I I I I I I I I I

20. What are the two basic types of interference?

______and

______

21. Constructive Interference occurs when ______

or when ______.

22. Determine the total height (or depth) of each pair of pulses below when they meet in the middle ______