# Waves Unit Study Guide

Urban and Civil

Nov 29, 2013 (4 years and 5 months ago)

85 views

Waves Unit Study Guide

1. What does opaque mean? Give 2 examples of

an opaque material.

Material that doesn’t let light go through.

Black plastic

Steel

Wood

2. How do we see color?

We see light that is reflected off an object. The
other colors

are absorbed.

3. What is frequency, and what unit is used to

measure it?

Number of wavelengths that pass a given point in
1 sec. Hz (Hertz)

4. Define pitch.

How high or low a sound is.

5. What is an electromagnetic wave, and give an

example of one.

Waves that can travel through mater or space.

infrared

visible light

ultraviolet light

x
-
rays

gamma rays

6. What does the outer ear do?

Collects sound waves & directs them into the ear
canal.

7. Define amplitude.

In a transverse wave = ½ the distance between
the crest & trough

8. Compare the speed of sound in different states

of matter.

Solid = fastest

Liquid = in between solid & gas

Gas = slowest

9. List the waves of the electromagnetic spectrum

in order from smallest wavelength to greatest

wavelength.

Gamma

x
-
ray

UV

i
nfrared

ultraviolet

microwaves

10. What is loudness?

Human perception of how much energy a sound
wave carries.

11. Define refraction.

Bending of a wave as
it moves from one medium
into another

12. What is rarefaction?

In a compressional wave = the area where
molecules are futher apart.

13. Define wavelength.

Distance between 2 identical parts of a wave.

Transverse waves = distance from the crest to
crest or trough to trough.

Compressional waves = distance from the middle
of 1 compression to the middle of the next or the
middle of a rarefaction to the middle of the next.

14. What is the difference between a concave

mirror and a convex mirror?

Concave mirror

surface curved inward: causes
light rays to come together

Convex mirror

surface that is curved outward:
causes light rays to spread out (diverge)

15. What is the difference between a concave lens

and a convex lens?

Concave lense

thicker at the edges = causes light

Convex lens

thicker at the center = causes light
rays to come together

16. Define lens.

Transparent object that has at least one curved
surface that causes light to be
nd.

17. What is a mechanical wave?

Thype of wave that can only travel through
matter.

18. Define translucent.

Allows only some light to pass.

Frosted or stained glass

19. What is a compression?

In a compressional wave = area where molecules
are
pushed closer together.

20. Define diffraction.

Bending of waves aroughd a barrier.

21. What does it mean to say a material is

transparent?

Allows nearly all light to pass through.

22. What is wave interference? Explain the two

types

of wave interference.

The ability of waves to combine and form a new
wave.

Constructive = new wave with a greater
amplitude is formed. (bigger)

Destructive = a new wave with a smaller
amplitude is formed. (smaller)

23. What is a compressional wave?

Type of mechanical wave

Matter in medium moves forward & backward
alon the direction of the wave.

24. Define reflection.

When a wave strikes an object/surface and
bounces off.

25. How does the pitch of sound vary

with
frequency?

As the pitch increases, so does the frequency.

26. What happens when a wave goes through a
small opening?

Waves will diffract or bend as it goes through a
small opening.

27. What happens when a wave moves from one
medium to another?

They refract (bend)

28.
Define transverse wave?

* Mechanical

* Electromagnetic

Mechanical = wave energy causes matter in the
medium to move up & down perpendicular to the
direction of the wave.

Electromagnetic = electric & magnetic fields move
up &
down perpendicular to the direction of the
wave.

29. Does sound move faster in water or air?

Water

30. Describe constructive interference.

The waves add together & form a bigger wave.

31. Describe destructive interference.

The waves subtract and

form a smaller wave.

32. Define Frequency.

The number of waves passing a given point per
second.

33. Define Amplitude.

In a transverse wave = ½ the distance between
the crest & trough

The amound of energy in a wave.

34.
Define diffraction.

Bending of waves around a barrier

35. Which waves do NOT need a medium in
which to travel?

Electromagnetic Waves (EM spectrum)

Radio, infrared, visible light, ultraviolet, X
-
rays, & gamma rays

36. How does the eye see an object?

We see light that
is reflected off an object. The
other colors are absorbed.

37. Why are some objects black?

Because they absorb all colors.

38. Why are some objects white?

Because they reflect all colors.

39. What is happening when you see a green
object?

All the
colors except green are being absorbed.

40. What does 60 hertz (Hz) stand for in a wave?

The wave’s frequency. It means that there is 60
wavelenghs per second.

41. Define Transparent

Material that allows nearly all light to pass
through.

42. What
is the relationship of wavelength to
frequency in the electromagnetic spectrum?

As the wavelength increases, the frequency
decreases.

43. Define Radio waves & what they are useful
for.

Radio waves are a low energy part of the
electromagnetic
spectrum and are used in cell

44. What kind of field do moving electrons
produce?

A magnetic field

45. What are gamma rays used for?

Cancer treatment and killing backteria in food.

46. What determines the different color
s of visible
light?

The wavelength

47. What is pitch?

The highness or lowness of a sound.

48. What is loudness?

The human perception of the energy in a wave.

49. Define a mechanical wave.

A transverse or compressional wave that can only
travel through matter.

50. Give 2 examples of a mechanical wave.

1.
Sound

2.
Ocean

3. Earthquake = produces both transverse &
compressional waves.

51. Draw & label a transverse wave

52. Draw & label a compressional wave