Physics II: 1-2, 11-12 Flashcards
zeroth law of thermodynamics
objects are in thermal equilibrium when they are at the same temperature
no net exchange of heat energy
a=b, b=c, then a=c
heat
transfer of thermal energy from a hotter object with higher temperature (energy) to a colder object with lower temperature (energy) until they come into thermal equilibrium (same temp)
convert C to K eq
K = C + 273
thermal expansion
describes how a substance changes in length or volume as a function of the change in temperature
linear expansion eq
ΔL = αLΔT
ΔL = change in length
α = coefficient of linear expansion
L = og length
volumetric thermal expansion eq
ΔV = βVΔT
what is the maximum distance that two objects can be from one another and still adhere to the zeroth law of thermodynamics?
no max
as long as two objects are in thermal contact and at the same temperature, they are in thermal equilibrium
isolated system
do not exchange matter or energy with surroundings
closed system
exchange energy but not matter with their surroundings
open systems
exchange both energy and matter with their surroundings
isolated system ex
bomb calorimeter
state functions
pathway independent and not defined by a process
process functions
describe the pathway from one equilibrium state to another
process function ex
work and heat
first law of thermodynamics
conservation of energy
the total energy in the universe can never decrease or increase
first law of thermodynamics eq
ΔU = Q - W
Q = energy transferred to the system as heat
ΔU > 0
when internal energy is positive, increasing temperature
ΔU < 0
when internal energy is neg, decrease temperature
Q > 0
heat flows into system
Q < 0
heat flows out of system
W > 0
work is done by the system (expansion)
W < 0
work is done on the system (compression)
according to the first law of thermodynamics, an increase in the total energy of a system is caused by…
transferring heat into the system
or
performing work on the system
according to the first law of thermodynamics, a decrease in the total energy of a system is caused by…
heat is lost from the system
or
work is performed by the system
what are the only two processes by which energy can be transferred from one object to another
work and heat
second law of thermodynamics
objects in thermal contact and not in thermal equilibrium will exchange heat energy such that the object with a higher temperature will give off heat energy to the object with a lower temperature until both objects have the same temp at thermal equilibirum
specific heat
c
amount of energy necessary to rasie one gram of a substance eby one degree C or K
specific heat of water
1 cal/gK
conduction
direct transfer of energy from molecule to molecule through molecular collisions
direct physical contact
convection
transfer of heat by the physical motion of a fluid over a material
only liquids and gases
radiation
transfer of energy by electromagnetic waves
can occur through a vacuum
heat transfer eq
q = mcΔT
q = heat gained or lost by an object
m = mass
c = specific heat
heat transfer eq when no temp change
q = mL
L = heat of transformation/latent heat of the susbtance
entropy
how much energy is spread out, or how widely spread out energy becomes in a process
change in entropy eq
ΔS = Qrev/T
Qrev = heat gained or lost in reversible process
T = temp in K
second law of thermodynamics eq
ΔSuniverse = ΔSsystem + ΔSsurroundings > 0
as the number of microstates increases, the potential energy of a molecule…
9is distributed over that larger number of microstates, increasing entropy
natural process
irreversible
what is the relationship between the entropy of a system and its surroundings for any thermodynamic process?
the entropy of a system and its surroundings will never decrease
it will always either remain zero or increase
isothermal
first law of thermodynamics reduces to:
Q = W
(bc ΔU = 0)
adiabatic
first law of thermodynamics reduces to:
ΔU = -W
bc Q = 0
isovolumetric
first law of thermodynamics reduces to:
ΔU = Q
bc W = 0
What is the difference between Heat (Q) and Specific Heat (c)?
Heat (Q) is the overall change in heat for a substance. Specific Heat (c) is the degree to which a given substance's temperature will increase based on the amount of heat added. It is the ease with which a substance will heat up.
You have 4.3 kg of water (c = 4186 J/kg⋅C; L = 2260 J/kg). How much Heat would it take to convert all of the water into vapor if the current temperature of the water is 53.7°C?
(A) 1,423
(B) 843,109
(C) 1,423,675
(D) 2,143,896
(B) 843,109
Qtotal = Qheat + Qphase Qtotal = mc∆T + mL Qtotal = (4.3)(4186)(100-53.7) + (4.3)(2260) Qtotal = (approx. 800,000 (actual: 833,390.74)) + (approx. 9,000 (actual: 9,718)) Qtotal = (approx. 809,000 (actual: 843,108.74))
CRB Which of the following statements about the 0th Law of Thermodynamics are true?
I. This establishes Temperature as a Phase Function.
II. This establishes Temperature as a fundamental property of matter
III. For Thermal Equilibrium to occur, the objects must be in contact and heat must pass.
(A) I only
(B) II only
(C) I and II only
(D) II and III only
(B) II only
Each of the following statements about the 0th Law of Thermodynamics are true:
I. This establishes Temperature as a State Function.
II. This establishes Temperature as a fundamental property of matter
III. For Thermal Equilibrium to occur, the objects must be in contact, meaning that heat is able to pass, but no heat actually will pass.
A convection oven uses heating elements to convert electrical energy to thermal energy, and then the movement of air in the oven can disperse that energy while it is pre-heating. Then, I put my meatloaf in and the air particles bombard the pan and meatloaf, increasing its temperature and cooking the meatloaf! Which mechanisms of heat transfer were used here?
I. Convection
II. Conduction
III. Radiation
(A) I only
(B) I and II only
(C) I and III only
(D) I, II and III
(B) I and II only
Convection was used when pre-heating the oven, and the heat transfer was mediated by hot air flowing away from the heating element.
Conduction was used when the air particles collided with the pan and meatloaf, increasing the temperature of the meatloaf.
Compare Heat (Q) and Temperature (T) in terms of thermal energy.
Heat is the Transfer of thermal energy between a system and its environment, whereas Temperature is the macroscopic features of having different thermal energy levels (i.e. a high temperature feeling “hot” and having high thermal energy).
Within a system, which of the following are possible?
I. Energy increases without the Surroundings changing
II. Energy is Destroyed
III. Energy is transformed from one form to another
(A) I only
(B) III only
(C) I and III only
(D) I, II and III
(B) III only
According to the Law of Conservation of Energy, Energy cannot be Created (I) nor Destroyed (II), only transformed from one form to another.
45.3 J of work is done on a certain gas, and gains 32.6 J of heat from its surroundings. By how much did its Internal Energy change?
(A) -77.9
(B) -12.7
(C) 12.7
(D) 77.9
(D) 77.9
∆U = ∆Q + ∆W ∆U = 32.6 + 45.3 ∆U = 32.6 + 45.3 ∆U = 77.9
Note that work done on a gas adds energy to the system, whereas work done by a gas subtracts energy from the system.
The area under the curve on a PV diagram is equal to what? What equation does this relate to?
The area under the curve on a PV diagram is equal to work according to the relationship W = P∆V where:
W = Work done to/by the gas. P = Pressure ∆V = Change in Volume
You look at a PV diagram and notice that the pressure increases from 12.5 atm to 34.6 atm while the Volume decreases from 55.6 L to 35.4 L. Can we use the W = -P∆V equation to solve for the work done? Explain.
No, the W = -P∆V equation cannot be used here because this equation only works for isobaric systems. Since both pressure and volume are changing here, the work could only be found by integrating or estimating the area under a PV curve on a graph.
What variables change in the ∆U = Q + W equation for each process?
(1) Isobaric
(2) Isochoric
(3) Isothermal
(4) Adiabatic
(1) Isobaric - W changes due to a change in V.
(2) Isochoric/metric/volumetric - W does not change due to Volume remaining constant.
(3) Isothermal - ∆U remains constant because T remains constant. W and Q also remain constant.
(4) Adiabatic - Q does not change. This is the definition of an Adiabatic process. The change of U is caused solely by a change in W.
how does an isothermal process look like on a P-V graph?
what is work?
hyperbolic curve
work is area under the curve
how does an adiabatic process look like on a P-V graph?
what is work?
hyperbolic curve
work is area under the curve
how does an isobaric process look like on a P-V graph?
flat line
how does an isovolumetric process look like on a P-V graph?
what is work?
vertical line
work done by gas = 0
spontaneous process
can occur by itself without having to be driven by energy from an outside source
does not necessarily happen quickly and may not go to completion
common method for supplying energy for nonspontaneous reactions
coupling nonspontaneous reactions to spontaneous ones
True or False? The Second Law of Thermodynamics states that Heat can flow from cold to hot as long as the overall heat flow is from hot to cold.
False. The Second Law of Thermodynamics states that Heat will never be seen to flow from cold to hot.
Compare the term microstate and macrostate?
A microstate is an exact arrangement/state of particles. There are often countless possible arrangements.
A macrostate is a generic state of particles. For instance, “mixed up” vs. “separated” are examples.
Why doesn’t heat ever flow from cold to hot?
Because statistically speaking there are way more microstates in which the fast moving particles and slow moving particles are mixed up.
True or false? The specific heat of a substance depends upon the phase the substance is in.
True. The specific heat of a substance depends upon the phase the substance is in.
How does Enthalpy (∆H) relate to Q?
Enthalpy (∆H) = Q
b
b
c
c
b
c
c
a
d
d
c
c
transverse waves
have oscillations of wave particles perpendicular to the direction of wave propagation (and perpendicular to direction of energy transfer)
ex: electromagnetic waves
longitudinal waves
have oscillations of wave particles parallel to the direction of wave propagation (and in the direction of energy transfer)
ex: sound waves
displacement in a wave
x
how far a point is from the equilibrium position
amplitude
A
magnitude of a wave’s maximal displacement
propagation speed of wave eq
v = fλ
period in terms of frequency eq
T = 1/f
crest
maximum point of a wave
point of most positive displacement
trough
minimum point of a wave
point of most negative displacement
wavelength
λ
distance between two crests or two troughs
frequency
f
number of cycles it makes per second
hertz
angular frequency
ω
another way of expressing frequency
radians/second
period
T
number of seconds it takes a wave to complete a cycle
inverse of frequency
angular frequency eq
ω = 2πf = 2π/T
principle of superposition
when waves interact with each other, the displacement of the resultant wave at any point is the sum of the displacements of the two interacting waves
interference
the ways in which waves interact ins pace to form a resultant wave
constructive interference
amplitude of the resultant wave = sum of the amplitudes of the two interfering waves
waves are exactly in phase with each other
destructive interference
amplitude of resultant wave = difference in amplitude between the two interfering waves
waves are exactly out of phase with each other
partially constructive/destructive interference
displacement of resultant wave = sum of the displacements of the two interfering waves
two waves are not quite perfectly in or out of phase with each other
traveling waves
have continuously shifting points of maximum and minimum displacement
standing waves
produced by the constructive and destructive interference of two waves of the same frequency traveling in opposite directions in the same space
antinodes
points of maximum oscillation
nodes
points where there is no oscillation
timbre
quality of sound
determined by natural frequency or frequencies of the object
forced oscillation
if a periodically varying force is applied to a system, the system will then be driven at a frequency equal to the frequency of the force
resonance
increase in amplitude that occurs when a periodic force is applied at the natural (resonant) frequency of an object
damping (attentuation)
decrease in amplitude by an applied or nonconservative force
how does applying a force at the natural frequency of a system change the system?
the object will resonate because the force frequency equals the natural (Resonant) frequency
the amplitude of the oscillation will increase
sound
longitudinal wave produced by mechanical disturbance of a material that creates an oscillation of the molecules in the material
sound travels fastest through…
solid with low density
sound travels slowest through…
gas with high density
within a medium, as density increases, the speed of sound ____
decreases
pitch
frequency of sound
infrasonic waves
sound waves with frequencies below 20 Hz
ultrasonic waves
sound waves with frequencies above 20,000 Hz
doppler effect
shift in the perceived frequency of a sound compared to the actual frequency of the emitted sound when the source of the sound and its detector are moving relative to one another
doppler effect eq
top sign = toward
bottom sign = away
doppler effect
the apparent frequency will be ___ than the emitted frequency when the source and detector are moving toward each other
higher
doppler effect
the apparent frequency will be ___ than the emitted frequency when the source and detector are moving away from each other
lower
doppler effect
the apparent frequency will be ___ than the emitted frequency when the source and detector are moving in the same direction
higher, lower, or equal
depending on the relative speeds
when the source is moving at or above the speed of sound, ____ can form
shock waves (sonic booms)
loudness/volume
percieved intensity
intensity
l
loudness of volume of a sound
related to a wave’s amplitude
intensity eq
I = P/A
P = power
A = area
how is intensity related to amplitude
intensity is proportional to the square of the amplitude
(2A = 4I)
how is intensity related to distance?
intensity decreases over distance
and some energy is lost to attenuation from frictional forces
sound level eq
β = 10 log(I/I0)
β = sound level
I = intensity of sound wave
I0 = threshold of hearing
new sound level eq
βf = βi + 10 log (If/Ii)
damping does not have an effect on…
frequency of wave -> pitch does not change
frequency of inc in volume eq
fbeat = | f1 - f2 |
closed boundaries
those that do not allow oscillation
correspond to nodes
open boundaries
those that allow maximal oscillation
correspond to antinodes
wavelength of standing wave (strings and open pipes)
λ = 2L / n
n = harmonic (positive nonzero integer)
L = length of string
frequency of standing wave (strings and open pipes)
f = nv/2L
v = wave speed
fundamental frequency
first harmonic
lowest frequency (longest wavelength) of a standing wave that can be supported in a given length of string
how to tell the harmonic series of a string
number of antinodes present tells you which harmonic it is
open pipes
pipes that are open at both ends
closed pipes
pipes that are closed at one end and open at the other
if the end of the pipe is open, it will support an ____
antinode
if it is closed, it will support a ___
node
1st, 2nd, and 3rd harmonics of an open pipe
1st, 3rd, and 5th harmonics of closed pipe
wavelength of standing wave (closed pipes)
λ = 4L / n
n = harmonic (only odd integers)
L = length of string
frequency of standing wave (closed pipes)
f = nv/4L
v = wave speed
ultrasound
uses high frequency sound waves outside the range of human hearing to compare the relative densities of tissues in body
electromagnetic waves
transverse waves that consist of an oscillating electric field and an oscillating magnetic field
magnetic field vectors are perpendicular to the direction of propogation
electromagnetic spectrum from lowest to highest energy
radio waves, microwaves, infrared, visible light, ultraviolet, x rays, gamma rays
speed of light in vacuum eq
c = fλ
visible spectrum
400-700 nm
ROYGBV
blackbody
ideal absorber of all wavelengths of light, which would appear completely black if it were at a lower temp than its surroundings
rectilinear propogation
light travels in a straight line through homogenous medium
reflection
rebounding of incident light waves at the boundary of a medium
law of reflection
incident angle will equal the angle of reflection as measured from the normal
θ1 = θ2
normal
line drawn perpendicular to the boundary of a medium
real image
light converges at the position of the image
virtual
light only appears to be coming from the position of the image but does not actually converge there
plane mirrors
flat reflective surfaces that cause neither convergence nor divergence of reflected light rays
always create virtual images that are the same size of the object
plane mirrors always create…
virtual images
reflection in plane mirror
center of curvature
C
point on the optical axis located at a distance equal to the radius of curvature
would be the center of the spherically shaped mirror if it were a complete sphere
radius of curvature
r
concave mirrors
converging systems
can produce real, inverted images OR virtual, upright images
convex mirrors
diverging systems
will only produce virtual, upright images
focal lenght
f
distance between focal point (F) and the mirror
o
distance between the object and the mirror
i
image distance
distance between the image and the mirror
key variables in geometrical optics
optics eq
all values have same units
i > 0
mirror: image is real, in front of mirror
lens: image is on opposite side of lens from light source (real)
i < 0
mirror: image is virtual, behind the mirror
lens: image is on same side of lens as light source (virtual)
magnification
m
dimensionless value that is the ratio fo the image distance and the object distance
magnification eq
m = -i/o
m < 0
inverted
m > 0
upright
|m| < 1
reduced
|m| > 1
enlarged
ray diagram for concave mirrors
object is placed beyond F
ray diagram for concave mirrors
object is placed at F
ray diagram for concave mirrors
object is placed between F and the mirror
ray diagram for convex mirrors
to find where the image is for a mirror
- draw the rays and find a point where any two intersect
- point of intersection marks the tip of the image
- if the rays you draw do not appear to intersect, extend them to the other side of the mirror, creating a virtual image
- ray parallel to axis - reflects back through focal point
- ray through focal point - reflects back parallel to axis
- ray to center of mirror - reflects back at same angle relative to normal
focal length of converging mirrors and lenses will always be…
positive
focal length of diverging mirrors and lenses will always be…
negative
o > 0
mirror: object is in front of mirror
lens: object is on same side of lens as light source
o < 0
mirror: object is behind mirror (extremely rare)
lens; obj is on opposite side of lens from light source (extremely rare)
r > 0
mirror: concave (converging)
lens: convex (converging)
r < 0
mirror: convex (diverging)
lens: concave (diverging)
f > 0
mirror: concave (converging)
lens: convex (converging)
f < 0
mirror: convex (diverging)
lens: concave (diverging)
refraction
bending of light as it passes from one medium to another
index of refraction eq
n = c/v
n = index of refraction
c = speed of light in vacuum
v = speed of light in the medium
snell’s law
for refracted rays of light as they pass from one medium to another
there is an inverse relationship between the index of refraction and the sine of the angle of refraction (measured from the normal)
snell’s law eq
n1 sin θ1 = n2 sin θ2
1 = medium from which the light is coming
2 = medium into which the light is entering
snell’s law
when light enters a medium with a higher index of refraction (n2 > n1)
the light bends toward the normal
snell’s law
when light enters a medium with a lower index of refraction (n2 < n1)
light bends away from the normal
total internal reflection
occurs when light cannot be refracted out of a medium and is instead reflected back inside the medium
happens when light moves from a medium with a higher index of refraction to a medium with a lower index of refraction with a high incident angle
results with any angle of incidence greater than critical angle
critical angle
minimum incident angle at which total internal reflection occurs
critical angle eq
θc = sin-1(n2/n1)
lenses
refract light to form images of objects
lenses vs mirrors
- lenses refract light, mirrros reflect light
- lenses have two surfaces that affect the light path - refracted twice
- light travels from obj through air into glass lens (1st surface)
- then, light travels through glass to other side, where it travels out of the glass and into the air (2nd surface)
converging lenses
reading glasses
for farsighted people
diverging lenses
standard glasses
need by nearsighted people
lensmaker’s eq
to find where image is for lens
- draw the rays and find a point where any two intersect
- point of intersection marks the tip of the image
- if the rays you draw do not appear to intersect, extend them to the other side of the mirror, creating a virtual image
- ray parallel to axis - refracts back through focal point of front face of lebs
- ray through or twoard focal point before reaching lens - refracts parallel to axis
- ray to center of lens - continues straight through with no refraction
lensmakers eq use
with lenses with non negligible thickeness
lenses and mirrors that have similar properties
concave mirrors and convex lenses - converging
convex mirrors and concave lenses - diverging
power in terms of focal length eq
P = 1/f
hyperopia
farsightedness
myopia
nearsightedness
multiple lens systems
focal lengh eq
1/f = 1/f1 + 1/f2 + … 1/fn
multiple lens systems
power eq
P = P1 + P2 + … + Pn
multiple lens systems
magnification eq
m = m1 x mx x … x mn
spherical aberration
blurring of the periphery of an image as a result of inadequate reflection of parallel beams at the edge of a mirror or inadequate refraction of parallel beams at the edge of a lense
dispersion
when various wavelengths of light separate from each other
chromatic aberration
dispersive effect within a spherical lens
t/f
the incident angle is always measured with respect to the normal
true
diffraction
bending and spreading out of light waves as they pass through a narrow slit
with a lens, diffraction may produce…
a large central light fringe surrounded by alternating light and dark fringes
young’s double slit experiment
shows the constructive and destructive interference of waves that occur as light passes through parallel slits, resulting in minima (dark fringes) and maxima (bright fringes) of intensity
interference
when waves interact with each other, the displacements of the waves add together
diffraction gratings
consist of multiple slits arranged in patterns
how does the diffraction pattern for a single slit differ from a slit with a thin lens?
single slit: does not create characteristic fringes when projected on a screen, although the light does spread out
slit lens system: additional refraction of light causes constructive and destructive interference, creating fringes
what wave phenomenon do diffraction fringes result from?
constructive and destructive interference between light rays
plane polarized light
all of the light rays have electric fields with parallel orientation
how is plane polarized light created
passing unpolarized light through a polarizer
circularly polarized light
all of th elight rays have electric fields with equal intensity but constantly rotating direction
What does it mean for a speaker to be π-phase Shifted? What does it result in in terms of Wave Interference?
For a speaker to be π-phase Shifted, it means that the speaker has been moved by 180 degrees. It results in points of Constructive Interference becoming Destructive Interference and vice versa.
For Young’s Double Slit Experiment, what equation will allow you to relate λ to θ (with Constructive Interference)?
mλ = dsinθ
m = the "order" (whole number integers such as 1,2,3...) λ = wavelength d = distance between the slits θ = angle between d and perpindicular line
True or false? Light Waves that have higher energies will also have larger diffraction angles (sinθ).
False. Light Waves that have higher energies will also have smaller wavelengths, which mean Smaller diffraction angles (sinθ).
Contrast the effects of a Convex and Concave lens.
If an object is on the same side of a lens as the image, this is considered to be a ________ image. If an object is on the opposite side of a lens as the image, this is considered to be a ________ image.
(A) virtual, virtual
(B) virtual, real
(C) real, real
(D) real, virtual
(B) virtual, real
If an object is on the same side of a lens as the image, this is considered to be a virtual image. If an object is on the opposite side of a lens as the image, this is considered to be a real image.
True or false? When there is only a single mirror/lens in play, a Real image is always Inverted and a Virtual image is always Upright.
True. When there is only a single mirror/lens in play, a Real image is always Inverted and a Virtual image is always Upright.
To really understand when lenses will lead to Virtual, Real, Upright and Inverted Images, Try drawing out Lens diagrams where there are Real Inverted images and Virtual Upright images. (Hint: Think of where the object and image must be!)
You are in physics lab and your lab instructor tells you to use two lenses. The second lens that you use will have what as its object?
(A) The object from the first lens
(B) The image from the first lens
(C) The image from the second lens
(D) None of the above
(B) The image from the first lens
The first lens will produce an image, which will then be the object for the second lens.
What does it mean to say that a lens has a high Power?
To say that a lens has a high Power is to say that the lens is better at bending light.
A person who is farsighted will form the image __________ their retina and should be prescribed a __________ lens.
(A) behind, concave
(B) behind, convex
(C) in front of, concave
(D) in front of, convex
(B) behind, convex
A person who is farsighted will form the image behind their retina and should be prescribed a convex lens.
A person who is nearsighted will form the image __________ their retina and should be prescribed a __________ lens.
(A) behind, concave
(B) behind, convex
(C) in front of, concave
(D) in front of, convex
(C) in front of, concave
A person who is nearsighted will form the image in front of their retina and should be prescribed a concave lens.
True or false? The image of a distant object will appear at a focal point for both convex and concave lenses.
True. The image of a distant object will appear at a focal point for both convex and concave lenses.
If an object is on the same side of a mirror as the image, this is considered to be a ________ image. If an object is on the opposite side of a mirror as the image, this is considered to be a ________ image.
(A) virtual, virtual
(B) virtual, real
(C) real, real
(D) real, virtual
(D) real, virtual
If an object is on the same side of a mirror as the image, this is considered to be a real image. If an object is on the opposite side of a mirror as the image, this is considered to be a virtual image.
Fill in the blanks: When talking about mirrors, _______________ angles are where the original ray of light meet the mirror, and the ____________ angles are the angles between the reflected ray and the mirror.
(A) Refracted, Reflected
(B) Incidental, Reflected
(C) Purposeful, Incidental
(D) Incidental, Purposeful
(B) Incidental, Reflected
When talking about mirrors, Incident angles are where the original ray of light meet the mirror, and the Reflected angles are the angles between the reflected ray and the mirror.
There are Concave/Converging and Convex/Diverging mirrors. Knowing both of the names, draw out how they affect rays of light.
Based on the relationship between the index of refraction of a medium and the speed of light in the medium, how would the Speed of Light in the Medium relate to Snell’s Law?
Since increasing the speed of Light in the medium would decrease the Index of Refraction, they are inversely related.
True or false? If the ray’s Angle of Incidence is greater than the Critical Angle, then there will be Total Internal Reflection and there is no reflected ray, only a refracted ray.
False. If the ray’s Angle of Incidence is greater than the Critical Angle, then there will be Total Internal Reflection and there is no refracted ray, only a reflected ray. All of the incident ray’s energy will stay in the medium it started in!
For which of the following scenarios could total internal reflection be possible?
I. n1 > n2
II. n1 = n2
III. n1 < n2
(A) I only
(B) III only
(C) I and II only
(D) II and III only
(A) I only
Total Internal Reflection is only possible when n1 > n2.
Describe the relationship between wavelength and index of refraction?
The smaller the wavelength of light, the higher the index of refraction.
Which color of light will bend the most as it enters a new medium?
(A) Red
(B) Blue
(C) Green
(D) Yellow
(B) Blue
Blue has the smallest wavelength and thus it will have the greatest index of refraction and bend the most.
CRB True or false? The image of a distant object will appear at a focal point for both convex and concave mirrors.
True. The image of a distant object will appear at a focal point for both convex and concave mirrors.
Fill in the blanks: Recall that Longitudinal waves have particles oscillate parallel to the direction the wave travels. ________________ Pushes the medium’s molecules closer together, and _____________ is the decompression that follows.
(A) Compression, Relaxation
(B) Compression, Rarefaction
(C) Suppression, Relaxation
(D) Suppression, Rarefaction
(B) Compression, Rarefaction
Recall that Longitudinal waves have particles oscillate parallel to the direction the wave travels. Compression Pushes the medium’s molecules closer together, and Rarefaction is the decompression that follows.
Air particles within a tube will oscillate up and down (vertically) or side to side (horizontally) within a tube?
The air particles will oscillate side to side (horizontally). Yet, we depict this displacement on a graph vertically. Don’t get confused. The air particles are actually oscillating side to side (horizontally).
A wave starts at a displacement of -5 units, moves to 0 displacement (point A), then moves to +5 displacement (point B), moves to 0 displacement again (point C), and finally moves back to -5 displacement once again (point D). At which point does the wave complete a single wavelength?
(A) Point A
(B) Point B
(C) Point C
(D) Point D
(D) Point D
A full wavelength occurs when a wave goes from an initial point of maximal displacement back to that very same point. It can be considered the unit that repeats itself in a wave.
If you blow over a tube, you will hear the Fundamental Wavelength. What is that?
(A) The wave with the smallest displacement that can still fit in the tube.
(B) The wave with the largest displacement that can still fit in the tube.
(C) The wave with the smallest wavelength that can still fit in the tube.
(D) The wave with the largest wavelength that can still fit in the tube.
(D) The wave with the largest wavelength that can still fit in the tube.
In this image, it would be the top wave.
You are observing a pipe organ in an old church. Which will play lower notes and why?
(A) Longer pipes will play lower notes due to allowing for a longer wavelength.
(B) Longer pipes will play lower notes due to allowing for a lower amplitude.
(C) Shorter pipes will play lower notes due to allowing for a longer wavelength.
(D)Shorter pipes will play lower notes due to allowing for a lower frequency.
(A) Longer pipes will play lower notes due to allowing for a longer wavelength.
Longer wavelengths correspond to lower frequencies, which correspond to lower pitches.
What equation can be used to relate length of the tube (L), wavelength (λ), and harmonic number (n) for an closed-closed pipe? Show how you might derive this equation based on the images you drew in the previous question.
λ = 2L / n (same equation as for open-open tubes)
λ = Wavelength L = Length of Tube n = Harmonic Number
What equation can be used to determine the new frequency due to the Doppler Effect?
You are singing a song as you run toward a wall. Put the following pitches in order of lowest to highest:
I. Pitch emitted as you sing
II. Pitch that hits the wall
III. Pitch that reaches your ear after reflecting off the wall
(A) I < II < III
(B) II < I < III
(C) III < II < I
(D) III < I < II
(A) I < II < III
In order of lowest to highest:
Pitch emitted as you sing < Pitch that hits the wall < Pitch that reaches your ear after reflecting off the wall
Electromagnetic Waves are based on the idea that:
(A) Electric Fields create Magnetic Fields and vice versa.
(B) Changing Electric Fields create Magnetic Fields and vice versa.
(C) Electric Fields create changing Magnetic Fields and vice versa.
(D) Changing Electric Fields create changing Magnetic Fields and vice versa.
(D) Changing Electric Fields create changing Magnetic Fields and vice versa.
How do Electromagnetic Waves compare to Light Waves?
Light is one example of an Electromagnetic Wave.
Which light is more likely to damage your skin?
(A) Yellow Light
(B) Green Light
(C) Blue Light
(D) Orange Light
C) Blue Light
Blue Light is more dangerous as it has a higher frequency. Think about how Ultraviolet (UV) light is dangerous and how it has a high frequency.
True or false? The direction of Polarization of a wave is the direction that electrons would flow inside that electric field.
False. The direction of Polarization of a wave is the direction that the wave’s electric field oscillates, and is often represented as a plane
Oxidation will occur on which side of a Concentration Cell? Reduction? Why?
`Oxidation will occur on the less concentrated side, in order to produce more ions.
Reduction will occur on the more concentrated side in order to remove ions, creating an equilibrium between the concentrations on both sides.
Why is the Standard Cell Potential 0 in a Concentration Cell?
The same half-reaction is occurring in opposite directions on either side, having the same E⁰cell. For instance, for Zn2+ the E⁰red is -.76 while the E⁰ox is .76; thus when you add these together to get the E⁰cell, they cancel out.
The Standard Cell Potential for an Electrolytic Cell is equal to -5.4. Which of the following batteries could be used to drive the reaction forward?
I. 14.2 Volts
II. 8.3 Volts
III. 4.8 Volts
(A) I Only
(B) I and II Only
(C) III Only
(D) I, II, and III
(B) I and II Only
You would need a battery with at least as much voltage as the Standard Cell Potential, which is -5.4 in this case.
Note that the Standard Cell Potential is negative, because this is a non-spontaneous reaction.
Label a soundwave with the following terms:
(1) Amplitude
(2) Wavelength
(3) Equilibrium Position
Soundwave visual: http://www.mediacollege.com/audio/images/loudspeaker-waveform.gif
As frequency increases, the pitch becomes:
(A) Louder
(B) Softer
(C) Higher
(D) Lower
(C) Higher
Frequency is related to Pitch whereas Intensity is related to Loudness.
Your professor teaches you that sound waves travel at a speed of 343 meters/second. What is he really saying?
(A) The air particles affected by the sound wave are moving at 343 meters per second
(B) Your Tympanic Membrane is oscillating 343 times per second as you hear that sound.
(C) The oscillations in the air particle are propagating at a speed of 343 meters per second.
(D) The light affected by the sound wave is moving at a speed of 343 meters per second.
(C) The oscillations in the air particle are propagating at a speed of 343 meters per second.
In which of the following medium conditions would the speed of sound be the Slowest?
(A) High-Density Solid
(B) High-Density Gas
(C) Low-Density Solid
(D) Low-Density Gas
(B) High-Density Gas
Because there is more inertia with all of the dense gas particles, a High-Density Gas would be the slowest medium for sound to travel through.
You double the frequency of a sound wave, the velocity of the sound wave will:
(A) quadruple.
(B) double.
(C) remain the same.
(D) halve.
(C) remain the same.
The velocity will not change, but the wavelength will divide in half.
What two properties of the medium can change the speed of the sound wave?
(1) Stiffness (Resistance to Compression)
(2) Density
Put the following in order of slowest to fastest:
I. Velocity of Sound in a Solid
II. Velocity of Sound in a Liquid
III. Velocity of Sound in a Gas
(A) I < II < III
(B) II < I < III
(C) III < II < I
(D) III < I < II
(C) III < II < I
In order of slowest to fastest:
Velocity of Sound in a Gas < Velocity of Sound in a Liquid < Velocity of Sound in a Solid
What equation is used to relate Radius/Distance from the sound to Intensity?
I = P / (4πr^2)
I = Intensity P = Power r = Radius
How would doubling the amplitude affect the intensity of a sound wave?
(A) Cut it in half
(B) Double the intensity
(C) Quadruple the intensity
(D) No effect
(C) Quadruple the intensity
Intensity is proportional to Amplitude Squared, so doubling the Amplitude will Quadruple the Intensity.
Why is using Ultrasound waves better than lower frequency sound waves?
Lower frequency sound waves diffract (bend more), resulting in an inaccurate/blurry measure.
Which of the following statements about Waves are true?
I. When a wave enters into a different medium, its speed changes, but NOT its frequency.
II. The speed of a wave is determined by the wave and the characteristics of the medium, NOT its frequency.
III. Amplitude increases with increasing Wavelength.
(A) I only
(B) III only
(C) I and II only
(D) I, II and III
(C) I and II only
Each of the following statements about Waves are true:
I. When a wave enters into a different medium, its speed changes, but NOT its frequency.
II. The speed of a wave is determined by the wave and the characteristics of the medium, NOT its frequency.
Which of the following does Amplitude depend on?
(A) Frequency
(B) Wavelength
(C) Wave Speed
(D) None of the Above
(D) None of the Above
Amplitude depends on how much energy was added to the wave at its creation. It is not affected by Frequency, Wavelength or Wave speed.
