Math/Physics Flashcards

Question 1

Q

What is potential energy? What are the types of potential energy

Answer

A

Potential energy: the energy that is associated with a given object’s position in space or other intrinsic qualities of the system

Gravitaional potential energy (U=mgh)
Elastic potential energy (U= 1/2kx²)

Question 2

Q

What is forced oscillation?

Answer

A

If a periodically varying force is applied to a system, the system will be driven at a frequency equal to the frequency of the force
Note: If the frequency of the applied force is close to the natural frequency of the system, then the amplitude becomes much larger
Example: If a parent pushes a child on a swing at a frequency nearly equal to the frequency at which the child swings back toward the parent, the arch of the swinging child will become larger and larger

Question 3

Q

What is total mechanical energy? What is the associated equation?

Answer

A

The sum of an object’s potential and kinetic energy

E= U+ K

U= mgh or 1/2kx²

Question 4

Q

What is the equation to determine a scalar quantity from two vectors?

Answer

A

A ⋅ B = |A| |B| cos θ

Question 5

Q

With regard to total internal reflection, what is the equation that is derived from Snell’s Law, that allows us to calculate the critical angle?

Answer

A

θ_C = sin^-1 (n₂/n₁)

Think:

n1 sin θ1 = n2 sin θ2

If sin 90= 1, then and you solve for the other angle, you get the above equation

Question 6

Q

What is noise, scientifically?

Answer

A

Sounds that we do not find particularly musical, such as tapping a pencil, hitting a chair, or crumpling paper

Question 7

Q

What is mechanical advantage? What are some tools that can provide this? What is the associated equation?

Answer

A

A measure of the increase in force accomplished by using a tool
Simple machines such as wedge, wheel and axel, level, pulley and screw provide mechanical advantage
Mechanical advantage = F_out/F_in
This is the ratio of the magnitudes of the force exerted on a object by a simple machine (F_out) to the force actually applied on the simple machine (F_in)

Question 8

Q

How long are γ- light rays?

Answer

A

< 10^-2 nm

Question 9

Q

What is Conduction? Convection? Radiation?

Answer

A

Conduction: the direction transfer of energy from molecule to molecule through molecular collisions

There must be direct physical contact between the molecules

Example: heat that conducts to your fingers if you touch a hot stove

Convection: transfer of heat by the physical motion of fluid over a material

Because convection involves flow, only liquids and gases can transfer energy by this means

Radiation: the transfer of energy by eletromagnetic waves

Radiation can transfer energy through a vaccuum, which the others cannot
How sun heats the earth

Question 10

Q

What is work? What is the associated equation when considering

Answer

A

Work is a process by which energy is transferred from one system to another

One of two ways in which energy can be transferred (the other is via heat)

Question 11

Q

What is timbre?

Answer

A

The quality of the sound; determined by the natural frequency of frequencies of the object

Question 12

Q

How long are radio waves?

Answer

A

10⁹ to 1m

Question 13

Q

What is Snell’s Law? What is the associated equation?

Answer

A

This is the law that describes how the speed of light is altered as it travels through a medium

n = c / v

n: index of refraction of the medium (dimensionless quantity)
c: speed of light in a vacuum
v: speed of light in the medium

n1 sin θ1 = n2 sin θ2

Question 14

Q

What is the specific heat of an object? What is the specific heat of water?

What is the equation which relates the heat gained or lost by an object and hte change in temperature of that object?

Answer

A

specific heat (c) of a substance is defined as the amount of heat energy required to raise one gram of sustace by one degree Celsius

Specific heat of water: 1cal/g×K

Equation: q=mcΔT

m: mass
c: specific heat

ΔT: change in temperature

Question 15

Q

What is the equation which provides the position of dark fringes with Young’s Double-Slit Expierment?

With regard to experiment, why does this specific type of pattern occur?

Answer

A

d sinθ = (n+1/2 )λ

d: distance between the two slits

θ: the angle between the line drawn from the midpoint between the two slits to the dark fringe and the normal

n: an integer indicating the number of the fringe

λ: the wavelength of the incident light

This pattern occurs because the diffracted rays emerging from two different slits interefere with one another; where there is constructive interefere, we see bright fringes and where there is destructive interference, we see dark fringes

Question 16

Q

What is gravitational potential energy? What is the associated equation?

Answer

A

An objects potential to do work, dependent on an object’s position with respect tto seom level identified as the datum (“ground” or zero potential energy position)
U=mgh

U: potential energy

m: mass
g: gravity
h: height
- Note the direct 1:1 relationship between U and all three variables

Question 17

Q

What type of waves are EM waves? Why?

Answer

A

EM waves are transverse waves because teh oscillating electric and magnetic field vecotrs are perpendicular to the direction of propogation

Question 18

Q

What regard to closed pipes, where there is a node at the closed end and an antinote at the open end, what is the equation which describes wavelength of the standing wave that can be supported by this pipe?

What is the frequencies of the standing wave supported by this pipe?

Answer

A

λ= 4L/n

n: only odd, positive integers (1, 3, f…)

f= nv/4L

v: wave speed

Question 19

Q

What is Kirchoff’s Loop Rule?

Answer

A

Around any closed circuit loop, the sum of voltage sources will always the equal to the sum of voltage (potential) drops
A consequence of the conservation of energy; all the electrical energy supplied by a source gets fully used up; no excess energy appears and no energy disappears that cannot be accounted for (but can change forms)

V _source = V _drop

Question 20

Q

What part of a wave does not change as it enters a new medium?

Answer

A

The frequency of the wave

Question 21

Q

What is an electric field? What is the equation which describes the magnitude of the electric field?

Answer

A

Electric field: the surrounding environment created by every electric charge (just like mass creates a gravitational field)

To determine this, we place a test charge (q) in the presence of a source charge (Q), the charge creating the electric field

E= F_e/q = kQ/r²

E: magnitude of the electric field

F_e: magnitude of the force felt by the test charge, q

k: electrostatic constant

Q: source charge magnitude

r: distance between the charges

Question 22

Q

How do pulleys work?

Answer

A

We are able to lift heavy objects to the desired height by using a smaller foce through a greater distance, in order to lift this heavy object to its final height
Example: There is a crate that must be lifted to a shelf 3 meters above then ground, then both sides of the supporting rope must shorten by 3 meters, an dh the only way to accomplish this is by pulling through 6 meters of rope

Question 23

Q

What is rotational equilibrium?

Answer

A

Exists only when the vector sum of all the Torques acting upon an object is zero
Called the second condition of equlibrium
Torques that generate clockwise rotation are considered negative; torques that generate counterclockwise rotation are positive

Question 24

Q

What is pressure? What is the associated equation?

Answer

A

Pressure: the ratio of force per unit area

P=F/A

P: pressure

F: force

A: area

Unit: Pascal (1Pa=1N/m²)

Question 25

Q

What is the speed of sound in air at 20C?

Question 26

Q

What is direct vs alternating current?

Answer

A

Direct current (DC): the charge flows in one direction only (like batteries)

Alternating Current (AC): the flow changes direction periodically (like the current supplied over long distances to homes and other buildings)

Question 27

Q

How is power related to resistance? What is the equation for this?

Answer

A

The rate at which energy is dissipated by a resistor is the power of the resistor

P= IV= I²R=V₂/R

I: the current through the resistor

V: the voltage drop across the resistor

R: resistance of the resistor

Note: the above equations can be derived by substitution using Ohm’s Law (V=IR)

Question 28

Q

What is temperature?

Answer

A

Molecular level: temperature is proportional to the average kinetic energy of the particles that make up the substance

At the macroscopic level, it is the difference in temperature between two objects that determines the direction of heat flow

Question 29

Q

What is the frequency of a wave? What is the symbol associated with this?

Answer

A

The number of wavelengths passing a fixed point per second
Measured in hertz (Hz)
Symbol: f

Question 30

Q

What is alpha decay?

Answer

A

A type of radioactive decay where the emission of an α-particle

α-particle: ⁴₂He

Question 31

Q

What is the equation that describes the magnitude of centripetal force?

Answer

A

F_c= mv²/r

Question 32

Q

What is electrical potential? What is its associated energy

Answer

A

The ratio of the magnitude of a charge’s electrical potential energy to the magnitude of the charge itself

V = U/q

V: electrical potential measured in volts

Can also say:

V = kQ/r

Note: Do not confuse this with electrical potential energy

Question 33

Q

What causes rotational motion?

Answer

A

Occurs when forces are applied against anbject in such a way as to cause the object to rotate around a fixed pivot pound, known as the fulcrum

Question 34

Q

While we hope that simple machines, such as pulleys, are conservative systems, a small amount of energy is lost to external forces, such as friction. How do we calculate the efficiency of a simple machine?

Answer

A

Efficiency = W_out/W_in= (load x load distance)/ (effort x effort distance

Often expressed as a percentage by multiplying the efficiency ratio by 100%

Question 35

Q

What is the work-energy theorem? What is the associated equation?

Answer

A

Offers a direct relationship between the work done by all the forces acting on an object and the change in kinetic energy of the object

W_net= ΔK = K_f-K_i

Question 36

Q

When you put a liquid in a cotainer what type of meniscus is usually created? Why?

Mercury, at room temperature, creates a different type of meniscus– what is this meniscus?

Answer

A

Liquid in a container creates a concave meniscus, a curved surface in which the liquid “crawls” up the side of the container a small amount, because the adhesive forces are greater than the cohesive forces
Mercury in a container will create a convex (backwards) meniscus, as the cohesive forces are greater than the adhesive forces

Question 37

Q

How would you calculate the magnetic force on a charge moving through a magnetic field?

How do you use the right- hand- rule to determine direction?

Answer

A

F_B= qvbsinθ

q: the charge
v: the magnitude of its velocity

B: the magnitude of the magnetic field

θ: the smallest angle between the vector v and the mangetic field vector B

Question 38

Q

How large is an Ångström?

Answer

A

1Å = 10^-10m

Question 39

Q

What are paramagnetic materials?

Answer

A

Have unpaired electrons, so these atoms have a net magnetic dipole moment, but the atoms in these materials are susually randomly oriented so that material itself creates no net magnetic field
Will become weakly magnetized in the presence of an external magnetic field, aligning magnetic dipoles of the material with the external field
Upon removal from the external field, the thermal energy of the individual atoms will cause the individual magnetic dipoles to reorient randomly
Examples: aluminum, copper, and gold

Question 40

Q

Does phase changes (e.g. solid to liquid) occur at consistent or at varying temperatures?

What equation can you use to determine the amount of heat used in a given phase change?

Answer

A

Phases changes occur at constant temperature and the temperature will not begin to change until all of the substacnce has been converted from one phase into another

Equation: q=mL

q: amount of heat gained or lost from material
m: mass of the substance

L: heat of taransformation

Cannot use q=mcΔT, because there is not change in temperature

Question 41

Q

What is spherical abberation?

Answer

A

A blurring at the periphery of an image as a result of inadeuqate reflection of parallel beats at the edge of a mirror or inadequate refraction of parallel beams at the edge of a lens

This creates an area of multiple images with very slightly distances at the edge of the image, which can be blurry

Question 42

Q

What are Newton’s Laws?

Answer

A

First Law: a body either at rest or in motion with constant velocity with remain that way unless a net force acts upon it; also known as inertia

Equation: F_net= ma=0

Second Law: An object of mass m will accelerate when the vector sum of the forces results in some nonzero resultant force vector

Equation: F_net=ma

Third Law: To every action, there is always an opposite but equal reaction

Equation: F_AB= -F_AB

Question 43

Q

By calculating the image distance (i), how do we know if an image is real or virtual?

Answer

A

If i has a positive value ( i > 0 ), then it is a real image, which implies that the image is in front of the mirror
If i has a negative value ( i < 0 ), then it is a virtual image, which implies that the image is behind the mirror

Question 44

Q

What is power? What is the associated equation?

Answer

A

The rate at which energy is transferred from one system to another

P= W/t= ΔE/t

P: power

W: work

t: time

SI Unit: Watt (W) = J/s

Question 45

Q

What is β decay?

Answer

A

A type of radio-decay in which a β-particle is emitted

β-particle: is an electron (given the symbol e^- or β^-)

During β^- decay, a neutron is converted into a proton and a β^-particle emitted
Since protons and neutrons have basically the same mass, the mass number does not change, but the atomic number goes up by 1

Question 46

Q

What is total internal reflection?

Answer

A

As light travels from a medium with a higher index of refrection to a medium with a lower index of refraction, the refracted angle is larger than the incident angle (θ₂ > θ₁)
As the incident angle is increased, the refracted angle also increases
At some point, this will increase to the critical angle (θ_C), for which θ₂equals 90 degrees
Total internal reflection occurs when all the light incident on a boundary is reflected back into the original materal, and results when any angle of incidence is greater than θ_C

Question 47

Q

What is a fluid?

Answer

A

Characterized the ability to flow and conform to the shapes of their containers

Question 48

Q

What is exponential decay? What is the associated equation?

Answer

A

n= n₀e ^-λt

n: the number of radioactive nulcei that have not yet decayed in the sample

n₀: the number of undecayed nuclei at time 0

λ: decay constant

t: the time passed since time 0

Question 49

Q

How do we evaluate capacitors in series? In parallel?

Answer

A

For capacitors in series,

1/C_s= 1/C₁ + 1/C₂ +1/C₃ + 1/C₄…

For capacitors in parallel,

C_s = C₁+C₂+C₃+C₄…

Question 50

Q

How would you relate the decay constant to the half-life?

Answer

A

λ = 0.693/T_1/2

λ: decay costant

Question 51

Q

Question 52

Q

What are longitudinal waves?

Answer

A

Waves in which the particles of the wave oscillate parallel to the direction of propagatoin
Sound waves are the prime example of longitudinal waves

(Image A)

Question 53

Q

How would one calculate the speed of a wave?

Answer

A

v= fλ

v: speed of the wave
f: frequency

λ: wavelength

Question 54

Q

What is the wavelength of a wave? What is the symbol that represents this?

Answer

A

The distance from one crest to the next crest (or one trough to the next)

Symbol: λ

Question 55

Q

What is intensity (in reference to sound)? What is the associated equation?

Answer

A

The average rate of energy transfer per area across a surface that is perpendicular to the wave

I=P/A

P: power

A: area

Question 56

Q

What is the equation for Torque (τ)?

Answer

A

τ = r x F= rFsin θ

r: the length of the lever arm

F: magnitude of force

θ: the angle between the lever arm and force vectors

Question 57

Q

What is current? What is the associated equation?

Answer

A

The amount of charge passing through a conductor per unit time

I = Q/Δt

Units: Ampère (1A= 1C/s)

Question 58

Q

If we have a string or open tube, what is the equation which associates the wavelength of the stranding wave and the length of the string that supports this standing wave?

What are the frequencies associated with these harmonics?

Answer

A

λ = 2L/n

n: positive, non-zero integer (called the harmonic)

L: length of the string

f= nv/2L

f: frequency
v: wave speed

Question 59

Q

What is the definition of “heat”?

Answer

A

The process by which a quantity of energy is tranferred between two object as a result in a difference in temperature

Question 60

Q

What is a traveling wave?

Answer

A

If a string is fixed at one end and is moved up and down, a wave will form and travel, or propogate, toward the fixed end
Called a traveling wave, becuase the wave moves
If the free end of the string is continuously moved up and down, there will be two waves: the original wave moving down the string toward the fixed end and the reflex wave moving away from the fixed end; the waves will interefere with each other

Question 61

Q

What is Ohmmeter?

Answer

A

Have their own battery of known voltage and then function as ammerteres through another point in the circuit
Use Ohm’s law to calculate resistance
Needs the circuit to be off

Question 62

Q

What is it called when two objects that are in thermal contact do not experience net heat flow?

Answer

A

Thermal equilibrium

Question 63

Q

When will turbulent flow occur? What is the assoicated equation?

Answer

A

Turbulent flow can arise when the spped of the fluid exceeds a certain critical speed

v_c= N_Rη/ρD

N_R: dimensionless constant called Reynolds number

η: viscosity of the fluid

ρ: density of the fluid

D: diameter of the tube

Question 64

Q

What is an ammeter?

Answer

A

Used to measure the current at some point within a circuit
Inserted in series where the current is being measured and sue the magnetic properties of the current-carrying wire to cause a visisble needle to vmove or a calibrated display of the current
If the curent is particualrly high, this will overwhlem the ammeter, and a special low resistance shunt is sued in parallel with the ammeeter to allow a reading
must have extremely low resistance so they do not change circut mathematics when inserted

Answer 63

A

A change in an objects position in space
Vector quantity
The displacement vector connects (in a straight line) the objects initial position and its final position
Displacement does not account for the actual pathway taken between the initial and final positions– only the net change in position from initial to final

Answer 64

A

Objects in thermal contact and not in thermal cequilibrium will exchange heat energy such that the object with a higher temperature will give off heat energy to the ojbect with a lower temperature until both objects have the same temperature at thermal equilibrium

Answer 65

A

Surface tension causes a liquid to form a thin but strong layer at the liquid’s surface
Results from cohesion, which is the attractive force that a molecule of liquid feels toward other molecules of the same liquid

Answer 66

A

Metallic conductivity

As seen in solid metals and the molten form of some salts
Materials which allow free flow of electric charge within them
Metal atoms can easily lose one or more of their outer electrons, which are then free to move around in the larger collection of metal atoms

Electrolytic conductivity:

Seen in solutions
Depends on the strenght of a solution (distilled deionized water is an insulator, but salt water is a conductor)
Since there is a direct relationship, you can use conductivity to determine concentration, but note that conductivity is always lower in non-ionic solutions than ionic solutions

Answer 67

A

The rate of change of velocity that an object experiences as a result of some applied force

Deceleration: acceleration in the opposite direction as the initial velocity

Answer 68

A

Start by pointing your thumb in the direction of vector A
Extend your fingers in the direction of vector B. You may need to rotate your wrist to get the correct configuration of thumb and fingers.
Your palm establishes the plane between the two vectors. The director your palm points is the direction of the resultant C.

Answer 69

A

The maximum magnitude of displacement of a wave, from the equilibrium

Symbol: A

Answer 70

A

Resolve the vectors to be added into their x- and y- components
Add the x-components to get the x-component of the resultant and the y-components to get the y-component of the resultant
Find the magnitude of the resultant by using the pythagorean theorum
Find the direction of the resultant by using the relationship θ = tan^-1 (R_y/R_x)

Answer 71

A

v = √(B/ρ)

v: velocity of sound

B: bulk modulus, a measure of the medium’s resistance to compression (B increases from gas to liquid to solid)

ρ: the density of the medium

Answer 72

A

Magnitude is measured as the rate of change of displacement in a given unit of time
SI units: m/s
Vector quantity

Answer 73

A

States that 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
The principle which explains constructive, destructive and partially constructive/destruction interference

Answer 74

A

A type of radio-decay in which a γ-ray is emitted

γ-ray: high energy photons

They carry no charge and simply lower the enrgy of the parent nucleus without changing the mass number or atomic number

Answer 75

A

When a vector is multiplied by a scalar, its magnitude will change but the direction will either be parallel or antiparallel to the original direction

B=nA, where A is the original vector, n is the scalar quantity and be is the new vector; the direction of B depends on the sign on n, if positive, then parallel, if negative, then antiparallel

Answer 76

A

The passing of a shock wave
As a shock wave passes, there is a very high pressure, followed by a very low pressure, which creates a sonic boom
A sonic boom can be heard any time that an object traveling at or faster than the speed of sound passes a detector

Answer 77

A

ΔU = Q-W

ΔU: change in the system’s internal energy

Q: energy transferred into the system as heat

W: work done by the system

Sign convention, see image

Answer 78

A

An expression of conservation of energy for a flowing fluid; states that the sum of the static pressure and dynamic pressure will be constant between any two points in a cloed system

P₁ +1/2 ρv₁² + ρgh₁ = P₂ +1/2 ρv₂² + ρgh₂

P: absolute pressure of fluid

ρ: density of fluid

v: linear speed of fluid
h: height of fluid

Answer 79

A

Power: the strength of the lens

P = 1/f

f: focal length

Units: diopters

Answer 80

A

The number of seconds per cycle (the opposite of frequency)

T= 1/f

Answer 81

A

F_g = Gm₁m₂/r²

Where G is the universal gravitational constant : 6.67x 10^-11N x m²/kg²

R: the distance between the centers of mass of the two objects

Answer 82

A

Plane mirrors- being flat reflective surfaces, cause neither diverge nor converge of reflected rays
Since convergence of the rays cannot happen, real images cannot be produced
Thus, all images are produced by a plane mirror are virtual

Answer 83

A

ΔL = αLΔT

ΔL: change in length

α: the coefficient of linear expansion

L: original length

ΔT: change in temperature

Answer 84

A

Cohesion: the attractive force that a molecule of liquid feels toward other molecules of the same liquid

Adhesion: the attractive force that a molecule feels toward the molecules of another substance

Answer 85

A

Will not easily distribute a charge over its surface and will not transfer that charge to another neutral object very well- especially not to another insulator
Most nonmetals are insulators

Answer 86

A

When waves are perfectly out of phase, the displacement always counteract each other and the amplitude of the resultant wave is the difference between the amplitudes of the interacting waves

Answer 87

A

FB= ILBsinθ

I: the current

L: length of the wire in the field

B: the magnitude of the magnetic field

θ: the smallest angle between the vector L and the mangetic field vector B

Answer 88

A

Vector: numbers that have magnitude and direction

Includes: displacement, velocity, acceleration and force

Scalar: numbers that have magnitude only and no direction

Incldues: distance, speed , energy, pressure and mass

Answer 89

A

Given a charge, a conductor will distribute the charge approximately evenly upon its surface
Able to transfer and transport charges
Often coceptualized as nuclei surrounded by a sea of free electrons that are able to move rapidly throughout the material and are only loosely associated with positive charges
Generally metals but can also include some ioninc solutions

Answer 90

A

m = - i / o

i: distance between the image and the mirror
o: distance between the object and the mirror
- If m= positive, then the image is upright
- If m= negative, then the image is inverted
- If |m| < 1, then the image is smaller than the object (reduced)
- If |m| > 1, then the image is greater than the object (enlarged)

Answer 91

A

n₁ sin θ₁ = n₂ sin θ₂

n₁ and θ₁ refer to the medium from which the light is coming
n₂ and θ₂ refer to the medium into which the light is entering
If n₂>n₁, light bends toward the normal
If n₂< n₁, light bends away from the normal

Answer 92

A

Exists only when the vector sum of all the forces acting on an object is zero
This is called the first condition of of equilibrium
Since the vector sum forces are equal to 0, it will not acclerate and will have constant velocity (constant speed and constant direction)

Answer 93

A

Since water is incompressible, the force on a piston is pushed down, it exerts a force which displaces a given volume of water; this same volume must be displaced on the opposite side, which creates a pressure and thus a force upwards

P= F₁/A₁ = F₂/A₂

Answer 94

A

When light travels through a homogenous medium, it travels in a straight line

Answer 95

A

The rate of flow through a given pipe or confined space, given laminar flow

Answer 96

A

Uses the bending of light rays to create a model of molecules
X-ray diffraction is often combined with protein crystallography during protein analysis
Dark and light fringes do not take on a linear appear, but rather a complex two dimensional image

Answer 97

A

1eV= 1.6 x 10^-19J

This is the amount of energy gained by an electron accelerating through a potential difference of one volt

Answer 98

A

U= 1/2 CV²

C: Capacitance

V: voltage

(The function of a capacitor is akin to a dam, the purpose of which is to store gravitational potential enerrgy by holding back a mass of water at a given height)

Answer 99

A

F_g= mg

F_g: weight of the object

m: mass
g: gravity

Answer 100

A

A measure of energy

J = (kg⋅m²)/s²

Answer 101

A

e = 1.60 x 10^-19C

proton: +1.60 x 10^-19C
electron: -1.60 x 10^-19C

Answer 102

A

v = v_o + at

x = v_ot +1/2at²

v² = v_o² +2ax

x = v_avgt

Answer 103

A

Static friction: exists between a stationary object and the surface upon which it rests

0 ≤ f_s≤ μ_sN

μ_s: coefficient of static friction

Kinetic friction: exists between a sliding object and the surface over which the object slides

f_k = μ_{k}N

μ_{k}: coefficient of kinetic friction

Answer 104

A

The rate of actual distance traveled in a given unit of time

Answer 105

A

A logarithmic scale used for measuring sound intensity

β= 10 log I/I_{0}

I: intensity of the sound wave

I_{0}: threshold of hearing (1 x 10^-12W/m²)

Answer 106

A

Nearsighted or myopia (can see near objects clearly) need diverging lenses
Farsighted or hyperopia (can see distant objects clearly) need convering lenses

Answer 107

A

Describes the relationship between the variables in a real lens; i.e. a lens that does not have negligible thickness

1/f = (n-1) (1/r₁ - 1/r₂)

Note: for almost all MCAT questions, lenses will have negligible thickness and this equation is not application

Answer 108

A

If the incident photon is above the threshold frequency of the metal, the photon will have enough energy to eject a single electron, and any exess energy will be convereted to kinetic energy in the ejected electron

K_max = hf - W

W: work function of the metal in question

Work function: the minimum energy required to eject an electron and is related to the threshold frequency of the metal

W=hf_T

Note: the exact kinetic energy can be anywhere between 0 and K_max; K_max is only achieved when all possible energy from the photn is transferred to the ejected electron

Answer 109

A

Lenses in contact are a series of lenses with negligible distances between them, behave as a single lens with equivalent focal length

1/f = 1/f₁ +1/f₂ +1/f₃ +1/f₄…1/f_n

Because power is the reciprocal of focal length,

P = P₁ + P₂ + P₃ + P₄… P_n

Answer 110

A

As a sound wave emanates outward for their source, it is though the waves are pushing against the interior wall of the ever-expanding balloon
Because the surface area of the sphere increases as a function of the square of the radius (A=πr²), sound ways transmit their power over larger and larger areas the further from the source

- Intensity is inversely proportional to the square of the distance from the source

Answer 111

A

System: a portion of the universe that we are interested in observing or manipulating; the rest is the surroundings

Isolated systems: are not capable of exchanging energy or matter with their surrounds; thus, the total change in internal energy must be zero

Example: bomb calorimeter

Closed system: Capable of exchanging energy, but not matter, with the surroundings

Example: gases in vessels with movable pistons

Open systems: can exchange matter and energy

Answer 112

A

Refers to an ideal absorber of all wavelengths of light, which would appear completely black if it were at a lower temperature than its surroundings

Answer 113

A

Softest sound: 1 x 10^-12 W/m²

Pain: 10 W/m²

Burst eardrum: 1 x 10⁴ W/m²

Answer 114

A

When light travel through a medium, different wavelengths travel at different speeds; the index of refraction of a medium affects the wavelength of light passing through the medium because of n=c/v
Disperseion: When various wavelengths of light separate from each other

Example: white light through a prism

Answer 115

A

Straight wire:

B = μ₀I/ 2πr

This is the magntidue of the magnetic field at a perpendicular distance, r, from the wire

Circular wire:

B = μ₀I/ 2πr

This is the magnitude of of the magnetic field at the center of the circular loop

μ₀: permeability of free space

Answer 116

A

The opposition within any material to the movement and flow of charge

Materials that offer almost no resistace are called conductors
Materials that offer very high resistance are called insulators

Answer 117

A

When small nuclei combine to form a larger nucleus
Example: the sun fuses four hydrogen nuclei to make one helium nucleus

Answer 118

A

Our perception of the frequency of sound
Lower frequency sounds have lower pitch; higher frequency sounds have higher pitch

Answer 119

A

By calculating the area enclosed by the corresponding Pressure-Volume curve
W=PΔV

In an isovolumetric process, the ΔV=0, so the change work done is 0

In an isobaric process, then W=PΔV

Answer 120

A

Air resistance, opposes the motion of an object; its value increases as the speed of an object increases
Therefore, an object in free fall wil experience a growing drag force as the magnitude of its velocity increases
Eventually this drag force will be euqal in magnitude to the weight of the object and the object will fall with constant velocity (Newton’s 1st Law)
This is the terminal velocity

Answer 121

A

Perpendicular: both
Shear forces: solids

Answer 122

A

The lowest frequency (longest wavelength) of a standing wave that can be supported in a given length of string
1st harmonic (i.e. n= 1)

Answer 123

A

Any moving charge creates a magnetic field
May be set up by the movement of individual charges, like electrons moving through space; by the mass movement of chargein the form a current through an copper wire, or by a permanent magnet

Unit: Tesla (1 N x s/ M x C)

Note: Teslas are large units, so 1 Tesla = 10⁴ Gauss

Answer 124

A

The flow of positiove charge (even though only negative charges are actually moving)

Answer 125

A

Resistivity: how good of a conductor a material is, intrinsically

ρ; unit: Ohm-meter (Ω-meter)

Length: the longer something is, the further the electron has to pass through; if length doubles, resistance doubles

L

Cross-sectional area: an increase in cross-sectional areea increases the number of pathways through a resistor (conduction pathways); the wide the resistor, the more current that can flow (think of a river)

A

Temperature: most conductors have greater esistance at higher temperatures due to increase thermal ossicillation of the atoms in the conductive material, which produces a greater resistance to flow

R= ρL/A

Answer 126

A

Imaginary lines that represent how a positive test charge would move in the presence of a source charge

Answer 127

A

When both ends of a string are fixed and traveling waves are excited in the string, certain wave frequenceies will cause interference between the traveling wave and its reflected wave such that they will form a waveform that appears to be stationary
The only apparent movmeent of the string is fluctuation of amplitude of fixed points along the length of the string
Nodes: points in the wave that remain at rest (where amplitude is constantly zero)
Antinodes: points midway between the nodes which fluctuate with maximum amplitude

Answer 128

A

States that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere

Example: if one were to squeeze a milk container, the applied pressure would be transmitted through the entire volume of the milk

Answer 129

A

When there are non-conservative forces, such as friction, air resistance, or viscous drag (a resistance created by fluid viscosity) acting on an object
W_{nonconservative}= ΔE= ΔU + ΔK
The work done by non-conservative forces will be exactly equal to the amount of energy “lost” from the system (it is actually just transformed into antoerh for of energy that is not accounted for in mechanical energy)

Answer 130

A

Solid to Liquid: fusion or melting
Liquid to Solid: freezing or solidifcation
Liquid to gas: boiling, evaporation, or vaporization
Gas to liquid: condensation
Solid to gas: sublimation
Gas to solid: deposition

Answer 131

A

The amount of energy that is released when nucleons (protons and neutrons bind together)
The more binding energy per nucleon released, the more stable the nucleus
The bound system is at a lower energy level than the unbound constituents, and this difference in erngy must be radiated away in the form of heat, light or other electromagnetic radion before the mass defect becomes apparent

Answer 132

A

Sounds produced by objects which vibrate at multiple natural frequencies (a fundamental pitch and multiple overtones) that are related to each other by whole number ratios

Answer 133

A

The capacitance of the parallel plate capacitor is dependent upon the geometry of the two conduction surfaces; for the simple case of the parallel plate capacitor, the capacitance is given by:

C= ε₀(A/d)

ε₀: permitivity of free space (8.85 x 10^-12F/m)

A: area of overlap of the two plates

d: separation of the two plates

Answer 134

A

ΔV = βVΔT

ΔV: change in volume

β: the coefficient of linear expansion

V: original length

ΔT: change in temperature

Note: that the coefficient of volumetric expansion is equal to 3 times the coefficient of linear expansion for the same material (β=3α)

Answer 135

A

The difference in the absolute pressure inside a structure (like a tire) compared to the atmospheric pressure outside; in other words, the amount of pressure in a closed space above and beyond atmospheric pressure

P_gauge = P - P_atm = (Po + ρgz) - P_atm

Answer 136

A

W= F⋅ d = Fd cos θ

W: Work

F: the magnitude of the force applied

d: the magnitude of the displacement through which the force is applied

Answer 137

A

The ratio of the magnitude of the charged stored on one plate to the potential difference (coltage) across the capacitor
Therefore, if a voltage V is applied acorss the plates of a capacitor and a charge Q collections on it (with +Q on the postive plate and -Q ont he negative plate), then…

C: Q/V

C: capacitance

Q: charge

V: voltage

Units: Farad (1F= 1C/V)

Answer 138

A

For magnitude: A x B = |A| |B| sin θ
To determine the direction, use the right hand rule

Answer 139

A

Fow rate: the volume per unit time; is constant for a closed system and is independent of cross-sectional area

Linear speed: a measure of the linear displacement of fluid particles ina given amount of time; the product of linear speed (v) and cross sectional area (A) provide flow rate

Does change with cross-sectional area

Q=v₁A₁=v₂A₂

Answer 140

A

F_{g, parallel} = mg sin θ

F_{g, perpendicular} = mg cos θ

Answer 141

A

v_avg= Δx/Δt

Answer 142

A

Certipetal force, which always points radially inward, keeps the object from breaking out of the circular path

Answer 143

A

When the waves are perfectly in phase, the displacements always add together and the amplitude of the resultant is equal to the sum of the ampluitudes of the two waves

Answer 144

A

Made of atoms with no unpaired electrons and that have no net magnetic fields
Are slightly repelled by a magnet, so can be called weakly antimagnetic
Examples: wood, plastics, water, glass and skin

Answer 145

A

Uses high frequency sound waves outside the range of human hearing to compare the relative densities of tissues in the body
Ultrasound machine consists of a transmitter that generates a pressure gradient, which also functions as a receiver that processes the reflected sound
Because the speed of the wave and the travel time is known, the machine can generate a graphical representation of borders and edges within the body, by calculating the transversed distance
Relies of refelction in order to visualize anything, so an interface between two objects is necessary

Answer 146

A

THe electric field between the plates of a parallel plate capacitor is a uniform electric field with parallel field vectors
The magnitude can be calculated by:

E=V/d

V: voltage

d: distance
- Note: the direction of the electric field at any point between the plates is from the positive plate toward the negative plate

Answer 147

A

When light of a sufficiently high frequency (typicallly, blue to ultraviolet light) is incident on a metal in a vacuum, the metal atoms emit electrons
Electronsliberated from the metal by the photoelectric effect will produce a net charge per time (a current)
The higher the intensity of the light beam, the greater the number of photons per unit time that fall on an electrode, the greater numer of electrons per unit time liberated from the metal

Answer 148

A

Because the electical potential is inversely prorpotional to the distance from the source charge, a potential difference will exist between two points that are at different distacnes from the source charge

(Remember: V=kQ/r)

If V_a and V_b are the electrical potentials at points a and b, respectively, then the potential differnece between them is the Voltage (V_b- V_aor ΔV)

ΔV = V_b- V_a= W_ab/q

Wab: the work needed to move a test charge, q, through an electic field from point a to point b

Answer 149

A

When an object is placed in fluid, it will sink into the fluid only to the point at which the volume of the displaced fluid exerts a force that is equal to the weight of the object

F_buoy= ρ_fluid V_{fluid displaced} g = ρ_fluid V_submergedg

Answer 150

A

The spontaneous dispersal of energy at a specific temperature; how much energy is spread out or how widely spread out energy becomes in a process

ΔS= Q_rev/T

ΔS: entropy

Q_rev: the heat that is gained or lost in a reversible process

T: the temperature in kelvin

Units: J/mol x K

Example: While water and ice at 0C have the same kinetic energy, the energy is dispered over a larger number of microstates in liquid water; therefore water has a higher entropy and by extension, it is indeed less organized than ice

Answer 151

A

50 - 10^-2 nm

Answer 152

A

Quantifies the magnitude of electrostatic force, F_e, between two charges

F_e= kq₁q₂/r²

k: Coulomb’s constant (8.99 x 10⁹N x m²/C²)

q1 and q2: magnitudes of the two charges

r: is the distance between the two charges

Answer 153

A

a dispersive effect within a spherical lens; depending on the thickness and curvature of the lens, there may be signficant splitting of white light, which results in a rainbow halo around images
Corrected for in visual lenses liek eyeglasses and car windows with special coatings that have different dispersive qualities than the lens itself

Answer 154

A

All the possible frequencies that a string can support

(n=1, n=2, n=3…) with regard to:

f=nv/2L

Answer 155

A

Concave mirrors are converging mirrors, because they cause parallel incident light rays to converge
Convex mirrors are diverging mirrors, because they cause parallel incident light rays to diverge

Answer 156

A

Dielectric material: insulation
When a dielectric material, such as air, glass, plastic, ceramic, or certain metal oxides, is introduced between the plates of the capacitor, it increases the capacitance by a factor called the dielctric constant (κ)

C’ = κC

C’: new capacitance

C: initial capacitance

Answer 157

A

Describes how far a particular point on the wave is from the equilibrium position, expressed as a vector quantity
Maximum displacement is the amplitude

Symbol: x

Answer 158

A

The particular type of vibration that occurs when an object is hit and thus begins to vibrate
This can be altered by changing some aspect of the object, for example, by putting in more or less water into a wine glass or tightening or loosening a string

Answer 159

A

A naturally occurring spontaneous decay of certain nuclei accompanies by the emission of specific particles

Answer 160

A

00 x 10⁸m/s
- While EM waves vary in frequency and wavelength, in a vacuum, all EM waves travel at the speed of light

Answer 161

A

Waves in which the direction of particle oscillation is perpendicular tot he propagation of the wave
Example: a wave in the stadium; the people (particles) go up and down, but the wave moves left to right

(Image B)

Answer 162

A

The energy stored by springs and other elastic systems
Every spring has a a characteristic length at which it is considered relaxed, or in equilibrium. When a spring is stretched from its equilibrium length, the spring has spring potential energy

U=1/2 kx²

U: potential energy

k: spring oconstant (a measure of the stiffness of a spring)
x: magnitude of displacement from equilibrium

Answer 163

A

When a large nulceus splits into smaller nuclei
Rarely occurs sponteaneously, but through the absorption of a low-energy neutron, fision can be induced in certain nuclei
Because the binding energy per nucleon is greatest for intermediate-sized atoms (intermediate-sized atoms are most stable), when small atoms combine or large atoms split, a great amount of energy is released

Answer 164

A

1mm - 700nm

Answer 165

A

Focal length (f): the distance between the focal point and the mirror

Note: f = r/2

Center of Curvature (C): a point on the optical ais located at a distance equal to the radius of curvature from the vertex of the mirror

1/f = 1/o +1/i = 2/r

o: the distance between the object and the mirror
i: the distance between the image and the mirror

Answer 166

A

The frequency that is often used in consideration of simple harmonicmotion in springs and pendula

ω= 2π/T=2πf

T: period

f: frequency

(Remember: T=1/f)

Answer 167

A

Takes into account the pathway traveled (which displacement does not)
Scalar quantity

Answer 168

A

A form of potential energy that is dependent on the relative position of one charge with respect to another charge or collection of charges

U = kQq/r

If charges are unlike (one positive and one negative) that potential energy will be negative
If the charges are alike (both positive or both negative), then the potential energy will be positive

Answer 169

A

β_f = β_i +10log(I_f/I_i)

I_f/I_i: the ratio of the final intensity to the initial intensity

Answer 170

A

F= 9/5C +32

K= C+ 273

Answer 171

A

Because displacement is pathway independent, the actual distance traveled from the initial to final position does not matter, assuming all forces are conservative
Therefore, aaplying a lesser force over a greater distance to achieve the same change in position (displacement) accomplishes the same amount of work

Answer 172

A

400 - 50nm

Answer 173

A

Viscosity: the resistance of a fluid to flow
Increased viscosity of a fluid increases its viscous drag, a non-conservative force that is analogous to air resistance

Answer 174

A

When a first object is thermal equilibrium with a second object and the second object is in equilibrium with the third, the first is also in equilibrium the the third and there will be no heat flowing between the objects

Answer 175

A

The change in the total internal energy of a system is equal to the amount of energy transferred in the form of heat to the system, minus the amount of energy transferred from the system in the form of work

A statement of the conservation of energy: the total energy in the unveise can never decrease or increase

Answer 176

A

Consist of multiple slits arranged in patterns
Can create color patterns similar to a prism as the different wavelengths interfere in characteristic patterns

Examples

CD or DVD; these act like diffraction grating
thin films may also cause interference patterns, because light waves reflecting off the external surface of the film interfere with light waves reflecting off the internal surface of the film (thin films are things like bubbles or oil puddles in puddles of water)

Answer 177

A

20Hz to 20,000Hz

Answer 178

A

The voltage drop between any two points in a circuit, given that electrical resistance results in an energy loss, which reflects a drop in electrical potential

V= IR

V: voltage drop

I: the current

R: the magnitude of resistance

Answer 179

A

The minimum frequency of light that causes ejection of electrons
Symbol: f_T
Depends on the type of metal being exposed to radiation
If the frequency of the incident photon is less than the threshold frequency, then no electron is emitted
If the frequency of the incident photon is more than the threshold frequency, then an electron will be ejected, and the maximum kinetic energy of the ejected electron will be equal to the difference between hf and hf_T

Remember: E=hf

E: energy of the photon of light

h: Planck’s constant, 6.626 x 10^-34 J s

Answer 180

A

The total pressure that is exerted on an object that is submerged in fluid (remember: fluids are both liquids and gases)

P= P_o + ρgz

P= absolute pressure

P_o= ambient pressure (pressure at the surface)

ρ = density of the fluid

g = acceleration due to gravity

z= depth of the object

Answer 181

A

Density: the ratio of mass to volume

ρ= m/V

Density of water: 1 g/ cm³

Answer 182

A

Measure of force

N = kg⋅m/s²

Answer 183

A

An object that is producing sound while traveling at or above the speed of sound allows wave fronts to build upon one another at the front of the object
This creates a much larger amplitude at that point
This highly condensed wave front is the shock wave
Can cause physical disturbances as it passes through objects

Answer 184

A

Light waves that are refelcted are not absorbed into the second medium; rather they bound off of the boundary and travel back throguh the first medium
Law of reflection: θ₁ = θ₂

θ₁: incident angle, measured from the normal

θ₂: reflected angle, measured from the normal

normal: line perpendicular to the surface

Answer 185

A

When a species absorbs a high-frequency light and then returns to its grounds state in multiple steps
Each step has less energy than the absorbed light and is within the visible range of electromagnetic spectrum

Answer 186

A

A longitudinal wave transmitted by the oscillation of particles in a deformable medium; sound can travel through solids, liquids, and gases but cannot travel through a vacuum

Answer 187

A

700nm to 400nm

Answer 188

A

Used to measure a voltage drop across two points in a circuit (wired in parallel to these two points)
Voltmeters use magnetic properties of a current-carrying wire; require a circut to be active
Ideally; has infinite resitance

Answer 189

A

When the electric fields of all the waves are oriented int he same diection (their electric field vectors are all parallel)

Answer 190

A

Increasing

ΔSuniverse = ΔS_system+ ΔS_surrounds > 0

Answer 191

A

When the frequency of periodic force is equal to a natural (resonant) frequency of the system
Example: shattering of a wine glass by loudly singing the natural frequency of the class; the glass will resonate (oscillate with maximum amplitude) and eventually shatter

Answer 192

A

For resistors in series, the current has no choice but to go through every resistor

Rs = R₁+R₂+R₃+R₄…

For resistors in parallel, we allow for more pathways for current to take

1/R_p= 1/R₁ + 1/R₂ +1/R₃+ 1/R₄

Answer 193

A

a_avg= Δv/Δt

Answer 194

A

c= fλ

c: speed of light
f: frequency

λ: wavelength

Answer 195

A

Subtracting one vector from another can be accomplished by adding a vector with equal magnitude - but opposite direction - to the first vector

A - B = A + (-B)

Answer 196

A

a sinθ = nλ

a: width of the slit

θ: the angle between the line drawn from the center of the lens to the dark fringe and the axis of the lens

n: an integer indicating the number of the fringe:

λ: wavelength of the incident light

Answer 197

A

When certain unstable radionuclides capture an inner electron that combines with a proton to form a neutron (while releasing a neutrino)
The atomic number is one les than the original, but the mass number is the same
Kind of like a reverse β-decay

Answer 198

A

A line on which the potential at every point is the same; the potential difference between any two points on an equipotential line is zero

Answer 199

A

Isothermal (ΔU= 0) so first law reduces to Q=W
Adiabatic (Q=0) so first law reduces to ΔU=-W
Isobaric (constant pressure); no special form

Isovolumetric (W=0) so first law reduces to ΔU=Q

Remember, first law of thermodynamics is ΔU= Q - W

Answer 200

A

x= m₁x₁ +m₂x₂+m₃x₃…/ m₁+m₂+m3…

y= m₁y₁ +m₂y₂+m₃y₃…/ m₁+m₂+m3…

z= m₁z₁ +m₂z₂+m₃z₃…/ m₁+m₂+m3…

Answer 201

A

1.013 x 10⁵ Pa= 760 mmHg= 760 torr= 1 atm

Answer 202

A

At any point or junction into a circuit, the sum of currents directed into that point equals the sum of currents directed away from that point

I _{into junction}= I_{out of junction}

Answer 203

A

Conservative forces: gravity and electrostatic forces

Non-conservative: frction and air resistance

Answer 204

A

Real image: an image is said to be real if the light actually converges at the point of the image

Distinguishing feature: real images can be projected onto a screen

Virtual image: an image is said to be virtual if the light only appears to be coming fromt eh position of the image but does not actually converge there

Answer 205

A

Two waves that have the same frequency, same wavelength, and amplitude and that pass throught he same space at the same time, whose crests and troughs line up.

Answer 206

A

Kinetic energy: the energy of motion; objects that have a mass and that are moving with some speed will have an associated amount of kinetic energy

K=1/2mv²

K: kinetic energy

m: mass in kilograms
v: speed in meters/second

SI Unit: Joule (kg⋅m²)/s²

Answer 207

A

When no cahrge is moving between the two terminals of a cell that are at different potential values

A potential difference (voltage)

Answer 208

A

The amount that a conductive material, such as copper wires, act as weak resistors themselves, offers some magnitude of resistance to current and causing a drop in electrical potential (voltage)

V: E_cell - ir_int

V: voltage provided by the cell

E cell: emf of the cell

i: the current through the cell

r_int: the internal resitance of the cell

Answer 209

A

Characterized by their ability to hold charge ast a particular voltage

Example: defibrillators; they charge, the charge can be released in one surge of power

Answer 210

A

F_g= ρVg

Answer 211

A

The difference between the mass of unbound nucleons (protons and neutrons) and the mass of boudn nucleons within the nucleus
The unbound constituents have more energy and, therefore, mroe mass thant he boudn constituents
The mass defect is the amoung of mass converted to energy during nuclear fusion

(E=mc²)

Answer 212

A

Have unpaired electrons and permanent atomic magnetic dipoles that are normally oriented randomly, so the material has no net magnetic dipole (like paramagnetic materials)
Will become strongly magnetized when exposed to magnetic field or under certain temperatures (unlike paramagnetic materials)
Examples: iron, nickle and cobalt

Answer 213

A

Intensity is proportional to the square of the amplitude
Thus, a doubling of the amplitude produces a sound wave that has four times the intensity

Answer 214

A

Describes the difference between the actual frequency of a sound and its perceived frequency, when the source of the sound and the sound’s detector are moving relative to one another
f_o: perceived frequency
f_s: emitted frequency

Answer 215

A

ρ_object / ρ_fluid = V_disp/V

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