Light and Sound Test

Question 1

Scientific Notation - how to write numbers in scientific notation and how to do calculations with numbers in
scientific notation (see helpful videos posted on Canvas

Answer 1

knowwwwww itttt

Question 2

Waves – know what the wavelength ( ), amplitude (A), and frequency ( ) are and common units for each;λ ν
be able to compare waves (how does their wavelength, frequency, etc. compare?)

Answer 2

wavelength- (lambda) how long a wave is (measured in meters)
Amplitude- how tall a wave is (A) (meters)
Frequency- (v) how frequent each wave would pass a line. (Hz)

Question 3

What is light?

Answer 3

light is the visible portion of the electromagnetic spectrum

Question 4

ROYGBIV - know relative wavelengths, frequencies, and energies (don’t need to memorize exact numbers
but need to know which has longest wavelength vs. shortest wavelength, etc.

Answer 4

ROYGBIV
goes from longer wavelength and lower frequency (R)
to
shorter wavelength higher frequency

Question 5

Know the major types of electromagnetic radiation and their energies, frequencies, and wavelengths
In relationship to one another - you don’t have to memorize specific values but you should know which
has longer vs. shorter wavelengths, etc. – (Red Martians Invade Venus Using X-ray Guns

Answer 5

Radio
Microwave
Infrared
Visible
Ultraviolet
X-ray
Gamma Ray

Wavelength- long to short
Frequency- low to high

Question 6

What is the numerical value of the speed of light (c)? (units for speed of light → meters/second)

Answer 6

3.0x10^8 m/sec

Question 7

How does light travel?

Answer 7

in waves

Question 8

Know the formulas c = wavelength x frequency and E = h x frequency (h, Planck’s constant,
will be provided) and be able to algebraically manipulate these equations to do various
calculations (see examples in textbook, Practice Problems for Light and Sound on Canvas,
and in Speed of Light Lab)

Question 9

Understand the relationships between wavelength and frequency
and between energy and frequency

Answer 9

wavelength+frequency= inversely related

energy and frequency = directly related

Question 10

Be able to identify the parts and functions of the eye (know cause of farsightedness and nearsightedness
and how these can be corrected with lenses - mentioned below again);

Answer 10

farsightedness- image doesn’t come into focus before it hits the retina= convex lens can bring the focus forward

nearsightedness- image comes into focus before it hits your retina = concave lens can push the focus back.

Question 11

Know the “Law of Reflection”

and why you can see your reflection in some objects but not in others even though they all
reflect light

Answer 11

Law of reflection- angle of incidence= angle of reflection

most objects arent smooth enough to see yourself, the texture means that the rays don’t reflect straight back like a mirror they go all over the place.

Question 12

Distinguish between plane, convex, and concave mirrors (seen in Reflection/Refraction Lab) and be able
to draw ray diagrams in order to determine whether an image would be upright or inverted, magnified or
diminished - know the uses of these types of mirrors; be familiar with the focal point/focus and center of
curvature (these would be labeled for you on an exam diagram) – **rules for ray diagrams posted on Canvas

Question 13

What is refraction? When and why does it occur? How does the angle of incidence compare to the
angle of refraction? (seen in Reflection/Refraction Lab

Answer 13

refraction is the bending of light- occurs like a straw in water- (when one object passes through two different mediums.
angle of incidence does not equal the angle of refraction

Question 14

What does the image through a pinhole camera look like? (seen in Reflection/Refraction Lab)

Answer 14

everything is upside down

Question 15

Know that a prism splits white light into component colors - what is the order of the colors and which color
is refracted most/least?

Answer 15

prism refracts light-
ROY G BIV
red refracted least
Violet refracted more.

Question 16

Colors - know the primary and secondary colors of light, primary and secondary colors of pigment, and how
these colors will combine (color diagram); also know the complementary colors of light and pigments (color
diagram

Answer 16

primaries of light: green red blue
secondaries of light: cyan yellow magenta

Primaries of pigment= cyan yellow magenta
secondaries of light = green red blue

complementaries are across from each other

Question 17

Shadows (what property of light causes shadows?)

Answer 17

rectilinear propagation- light travels in a straight line until interrupted by an opaque object.

Question 18

Opaque, transparent, translucent

Answer 18

Opaque= no light comes through
transparent= some light comes through
translucent- all light comes through

Question 19

Reflection, Phosphorescence, Fluorescence

Answer 19

reflection- see colors of light that bounce off object, see the colors reflected

phosphorescence- absorbs visible light slowly and re emits it “glow in the dark”

fluorescence- absoravs visible and UV light then re emits it as visible- seen as brighter.

Question 20

Types of light – natural sunlight, artificial fluorescent, incandescent

Answer 20

sunlight- gives continous spectrum- all colors present
flourescent- bright lines only- not continuos
incandescent- gives continuos spectrum, more like sunlight

Question 21

What causes sound? How does sound travel? (compression, rarefaction)

Answer 21

sounds are caused by vibrations
travels in waves
compressions are the maximum point on a sound wave
Rarefractions are the minimum points on a pressure wave.

Question 22

Know the characteristics of sound waves - wavelength, frequency, and amplitude and how these
are related to the pitch and loudness of a sound

Answer 22

Wavelength is just the length of the wave of sound (just like light)
Frequency is also called pitch
amplitude corresponds to a sounds loudness measured in decibles.

Question 23

Speed of sound – how fast in air? How does that compare with speed in liquids and solids?
Can sound travel in a vacuum (absence of particles)? Why or why not?

Answer 23

SOLIDS- 6,000 m/sec
liquids- 1500 m/sec
air- 340 m/sec

No, theres no matter for compression and rarefracction- so therefore it is silent in space.

Question 24

Distinguish between forced and sympathetic vibrations; give examples of each

Answer 24

Forced vibrations: when a vibrating object comes in contact with another option and causes it to vibrate as well.
(EX: phone on table)
Sympathetic Vibrations: occur when a vibrating object comes close to another object THAT HAS THE SAME NATURAL FREQUENCY, and the second object will start vibrating.
(EX: breaking a wine glass with your voice)

Question 25

Know the Doppler Effect and what a Sonic Boom is - when do these occur? Be able to explain both.

Answer 25

EX: when a train comes at you and it sounds loud and high pitched, then when it passes it sounds lower pitched.

explanation:
as the train moves toward you it is literally bunching up sound waves in front of it, when these “bunch up” they are compressed making the frequency greater- and higher frequency means high pitch
and likewise when the train passes the waves behind it are more spread out which mean lower frequency= lower pitch

a sonic boom occurs when an airplane/rocket breaks through the sound barrier
If a sound producer is traveling at great enough speed it will catch up with the sound waves it has produces. this causes the waves to build up to a point at the front of the aircraft, this is called the sound barrier, when the aircraft goes fast enough it will break this barrier causing a shock wave or a “sonic boom”

Question 26

Speed of sound - know the formula: speed = wavelength x frequency, units for each, and be able to
algebraically manipulate this equation to solve for different unknowns (more on speed of sound below) –
(see examples in textbook, Practice Problems for Light and Sound on Canvas, and in Speed of Sound Lab)

Question 27

Human Ear - know parts of the ear and the function of sections (outer, middle, inner) and of the
individual parts of the ear; know the range of human hearing

Answer 27

OUTER EAR:
pinna+ ear cannal

MIDDLE EAR:
eardrum
malleus
incus
stapes

INNER EAR
Cochlea
Auditory nerve

Question 28

Know examples of each of the 3 classes of instruments

Answer 28

Percussion: drums
stringed: guitar
wind: flute

Question 29

Know how each class generates sound

Answer 29

percussion: when the instrument is hit it vibrates, causing the sound
string: when the strings vibrate, vibrations are transferred to the air and are amplified electronically
wind: blowing through a tube, as air travels down the tube it vibrates

Question 30

Know how pitch varies for each class

Answer 30

percussion: changing the size shape or tension of the vibrating material
string: adjusting the tension of length of the strings
wind: covering or opening holes in the instrument tube

Question 31

Law of Reflection (think back to light section as well)

Answer 31

it is the same: the angle of incidence equals the angle of reflection. and echo is simply a sound reflection.

Question 32

Know examples of how sound reflection is useful (examples of how sound reflection is used)

Answer 32

sound reflection is useful in SONAR and echolocation,

Question 33

Echos - how far from reflecting surface to hear an echo and why? What are reverberations?

Answer 33

you must stand 55 feet from the reflecting surface because….
you can only hear it 1/10 of a second after the of sound, so 345 meters, x 1/10th of a sound is 34.5 meters,
for an echo to happen if has to go halfway, reflect off of a surface and come back in that 34.5 meters.
So 34.5 m in have is 55 ft

Question 34

What is echolocation? What is SONAR? How are these used? Give examples of animals that
use echoes for navigational purposes (included in Speed of Sound Lab

Answer 34

SOund
NAvigation
Ranging
method of echolocation used to determine the location of underwater formations or submariens- ie fishermen looking for a school of fish.

echolocation used by animals to detect where other things are based on the reflected sound coming back to the animal
ex: bats

Question 35

Methods used to reduce noise indoors

Answer 35

Add carpets and pillows avoid long flat surfaces that will reflect sound

Question 36

advantage of two eyes:

Answer 36

depth perception

Question 37

know what persistence of vision is

Answer 37

an optical illusion that occurs when the human eye continues to see an image after it has disappeared from view. (lets us see flipbooks and movies)