03 waves (concepts)

Question 1

a progressive wave is a disturbance or vibration that travels from one point to another, carrying ________ and _________.

Answer 1

energy & momentum

Question 2

a vibration where the displacement above and below the equilibrium position are EQUAL

Answer 2

simple harmonic motion

Question 3

when particles of a medium undergo simple harmonic motion, it is considered a ____________________.

Answer 3

sinusoidal (periodic) wave

Question 4

maximum disturbance of a wave

Answer 4

amplitude

Question 5

wave classification

mechanical wave

Answer 5

require a medium to propagate

Question 6

wave classification

electromagnetic wave

Answer 6

travel through vacuum s medium

Question 7

differentiate waves by particle driection
* transverse
* longitudinal
* surface

Answer 7

• transverse: perpendicular
• longitudinal: parallel
• surface:both parallel and perpendicular (circular)

*see figures on PPT for reference

Question 8

parts of longitudinal wave

Answer 8

• compression: compressed part
• rarefaction: stretched part

Question 9

sound waves are transmitted better in ______________

A. gases than in solids
B. liquids than in solids
C. gases than in liquids
D. solids than in liquids

Answer 9

solids than liquids

Question 10

points in a wave are vibrating ________________ if those points undergo vibrations in the “same” direction

Answer 10

in-phase vibrations

Question 11

a wave that oscillates in place

Answer 11

standing wave

• Node: a stationary point
• Antinode: a point with maximum disturbance
• Segment: distance between successive nodes

Question 12

any frequency **higher than **the fundamental frequency

Answer 12

overtone

(Ex) F = 50 Hz
Overtone: 51, 52, 53, 54…

Question 13

an overtone with a frequency that is a multiple of the fundamenatl frequecy (or first harmonic)

Answer 13

harmonic

(Ex) F1 = 50Hz
Harmonic: 50, 100, 150, 200…

Question 14

wave behaviors

**bouncing off **of waves upon hitting a boundary

Answer 14

Reflection

see PPT for figure reference
* Specular Reflection: smooth surface
* Diffused Reflection: rough surface

Question 15

law of reflection

Answer 15

1. incident ray, reflected ray, and normal to the boundary all lie in the same plane
2. θi = θr (angle of incidence = angle of reflection)

see PPT for figure reference

Question 16

A light ray strikes a flat mirror at an angle of 35° with
the surface of the mirror. What is the angle of reflection
relative to the normal?

A. 35°
B. 45°
C. 55°
D. 90

Answer 16

55°

90 - 35 = 55

Question 17

If the total angle between the incident ray and the
reflected ray is 130°, what is the angle of incidence?

A. 90°
B. 65°
C. 50°
D. 25°

Answer 17

65°

130/25 = 65
θi = θr

Question 18

Which of the following describes the ‘normal’ in the
context of reflection?

A. A line perpendicular to the mirror’s surface at the point of incidence.
B. A line parallel to the mirror’s surface.
C. A line that shows the path that light takes before hitting the mirror.
D. A line that shows the path that light takes after hitting the mirror

Answer 18

A

Question 19

bending of a wave as it moves from one medium to another

Answer 19

refraction

bending is either “towards” or “away”

Question 20

Refraction

bending towards the normal

Answer 20

• 2nd medium is denser than the 1st
• θi > θr or θ1 > θ2
• refracted ray is closer to the normal

Air –> Water/Glass

Question 21

bending away from the normal

Answer 21

• 1stmedium is denser than the 2nd
• θr > θi or θ2 > θ1
• refracted ray is farther from the normal

Glass/Water –> Air

Question 22

A hunter is standing on the edge of a river trying to
spear a fish. Where should he aim to catch the fish?

A. Exactly where he sees the fish
B. Below where he sees the fish
C. Above where he sees the fish
D. It does not matter where he aims.

Answer 22

below where he sees the fish

Question 23

refraction

as light travels from one medium to another, its _____________ will _________ but its ________________ is _______________

Answer 23

speed will change
frequency is constant

Question 24

ratio of speed of light in vacuum and the speed of light in a certain medium

Answer 24

index of refraction (n)

n = c/v

Question 25

**speed of light in vacuum (c)**

Answer 25

**3 x 10 ^ 8 m/s**

Question 26

index of refraction and wave speed are ----

Answer 26

**inversely proportional**

Question 27

# refraction denser medium = ?

Answer 27

**denser medium = lower speed = higher index of refraction**

Question 28

In the spectrum or band of colors, violet is the least visible because it __________. A. is the most refracted B. is the least refracted C. is not refracted D. just wants to be seen

Answer 28

**most refracted** ## Footnote Violet: high refraction; short wavelength (least visible)

Question 29

white light splits into constituent colors when passing through a dispersive medium, such as a prism or water droplets

Answer 29

**dispersion** ## Footnote this occurs because of different wavelengths (colors) of light travel at different speeds in a material, causing them to refract by different amounts

Question 30

𝒏𝟏𝒔𝒊𝒏𝜽𝟏 = 𝒏𝟐𝒔𝒊𝒏𝜽2

Answer 30

**Law Refraction/Snell's Law** ## Footnote see PPT for figure reference

Question 31

occurs when a wave hits the boundary between two mediums and gets reflected instead of being refracted

Answer 31

**total internal reflection** ## Footnote see PPT for figure reference

Question 32

# total internal reflection * (1) ______________ is the maximum θ1 wherein refraction can still occur * when (1) is reached ( where θ1 = θc), then θr = (2) * total internal reflection occurs when (3) ______________

Answer 32

**(1) crticial angle** **(2) 90°** **(3) θ1 > θc** ## Footnote see PPT for figure reference ***ENDOSCOPE use total internal reflection within fiber optic bundle to illuminate and visualize internal body cavitites**

Question 33

bending of a wave around the edges of an object or through an opening (aperture).

Answer 33

**diffraction** ## Footnote see PPT figure for reference like refraction but the waves DO NOT pass through

Question 34

occurs when two waves meet while moving along the same medium

Answer 34

**interference** ## Footnote it is either** constructive or destructive**

Question 35

# interference * ligh passing through two narrow slits **diffracts and interferes**, creating a pattern of bright and dark fringes on a screen; * it demonstrates the **wave nature of light**

Answer 35

**Young's Double Slit Experiment** ## Footnote see PPT figure for reference

Question 36

**constructive interference**

Answer 36

amplitudes **add up**; results to a **larger wave**

Question 37

**destructive interference**

Answer 37

amplitudes **cancel out each other**; results to a **smaller wave or a flat line**

Question 38

# sound wave when a sound wave hits the eardrum, it results in the sensation of sound, with frequencies between __________________

Answer 38

**20Hz to 20KHz** ## Footnote **Sound wave:** a longitudinal wave in a medium

Question 39

# sound waves (1) infrasonic vs (2) ultrasonic waves

Answer 39

(1) sound waves **below 20Hz** (2) sound waves **above 20KHz**

Question 40

speed of sound in air at 0°C is taken as ____________

Answer 40

** 331 m/s** ## Footnote **For every 1°C increase in temperature,** the speed of sound in air increases by approximately **0.60 m/s.**

Question 41

(1) Loudness (2) Intensity

Answer 41

* **Loudness** is the ***subjective*** measure of how humans perceive sound. * **Intensity** is the **objective** measure of the sound's power

Question 42

alternations of maximum and minimum intensity

Answer 42

**beat** ## Footnote The number of **beats per second** is equal to the difference between the frequencies of the two waves that are combined

Question 43

change in a wave's observed frequency due to the relative motion between the wave's source and the observer

Answer 43

**doppler effect** the frequency increases as the source and the observe become closer