Mcat Physics

Front 1

sin 0, 30, 45, 60, 90, 180

Back 1

0, 1/2, sqrt2/2, sqrt3/2, 1, 0

Front 2

cos 0, 30, 45, 60, 90, 180

Back 2

1, sqrt 3 /2, sqrt2/2, 1/2, 0, 1

Front 3

one angstrom

Back 3

10^-10 m

Front 4

1 eV

Back 4

1.6 E-19 J, the energy acquired by an e- accelerating thru 1 V

Front 5

giga

Back 5

G/B = 10^9

Front 6

pico

Back 6

p = 10^-12

Front 7

torque

Back 7

rF sin(theta) = r cross F, negative is cw and positive is ccw

Front 8

translational motion equations

Back 8

v = v(o) + at, x = v(o) t + 1/2at^2, v^2 = v(o)^2 + 2ax,

Front 9

centripetal acceleration

Back 9

v^2 / r

Front 10

work

Back 10

Fd cos(theta) = F dot d = change in KE

Front 11

efficiency

Back 11

work out / work in = load x load dist / effort x effort d

Front 12

momentum

Back 12

mv

Front 13

impulse

Back 13

J = Ft = change in momentum

Front 14

power

Back 14

work / time, and 1 Watt = 1 J/s

Front 15

potential energy of a spring

Back 15

U = 1/2 k x^2

Front 16

center of mass

Back 16

com = sum of m(i)x(i) / sum of m(i)

Front 17

center of gravity

Back 17

sum of weight(i)x(i) / sum of weight(i) where w=mg

Front 18

average force of impact

Back 18

mass x average acceleration, where <a> = delta v / delta t... so if you increase the collision time, you decrease the force of impact ; also impact force = change in momentum / time

Front 19

joule

Back 19

1 N *m

Front 20

energy lost to heat due to friction

Back 20

equals work done by friction

Front 21

absolute zero

Back 21

0K, -273 C, -460 F

Front 22

freezing and boiling of water

Back 22

freezing: 273 K, 0 C, 32 F boiling: 373 K, 100 C, 212 F

Front 23

celsius to farenheit

Back 23

Tf = (9/5)Tc + 32

Front 24

temperature measures...

Back 24

the average random KE of the molecules of a substance (NOT the total KE)

Front 25

thermal expansion, length

Back 25

change in L = alpha * L * (change in T) where alpha is the coefficient of linear expansion

Front 26

percent change in length or volume

Back 26

change in L / L or change in V / V

Front 27

thermal expansion, volume

Back 27

change in V = beta * V * change in T where beta = 3 *alpha

Front 28

conduction

Back 28

heat transfer thru collisions

Front 29

convection

Back 29

heat transfer thru mass motion of heated material, e.g. plumes of smoke

Front 30

radiation

Back 30

heat transfer via electromagnetic waves

Front 31

1 Cal

Back 31

is 10^3 calories = 3.97 Btu = 4184 J

Front 32

heat gained or lost during a temperature change

Back 32

Q = m*c*change in T (if Q>0, heat is gained), where c = specific heat

Front 33

specific heat

Back 33

heat required to raise the temperature 1K or 1C of 1 kg of a substance

Front 34

heat of transformation

Back 34

L = heat gained or lost during a phase change, Q = mL, can be heat of fusion or vaporization

Front 35

pressure

Back 35

is (normal) force per unit area, F/A, tmeasured in Pa or atm

Front 36

1 pascal

Back 36

N/m^2

Front 37

1 atm

Back 37

the pressure at sea level = 1.1013 E5 Pa

Front 38

change in internal energy of a system

Back 38

delta U = Q - W, heat transferred to system - work done by system

Front 39

work done by a system, isobaric

Back 39

W = P*change in V (isobaric = constant P)

Front 40

adiabatic

Back 40

no heat transfer, Q = 0 so change in U = -W

Front 41

if volume is constant?

Back 41

no work is done by the system, W=0 so change in U = Q

Front 42

if a closed cycle?

Back 42

no change in internal energy, so U=0 and Q=W

Front 43

isothermal

Back 43

constant temperature

Front 44

for a reversible isothermal process, what is the change in entropy?

Back 44

delta S = Q/T

Front 45

in an isolated system, change of entropy?

Back 45

can never decrease (energy must be put into a system for entropy to decrease), but it will increase if the rxn is irreversible. No change if rxn is reversible.

Front 46

density

Back 46

p = m/V ; measure in kg/m^3

Front 47

density of water

Back 47

10^3 kg/m^3 or 1 g/cm^3

Front 48

weight from density?

Back 48

weight = mg = pVg (mass = density * volume)

Front 49

specific gravity

Back 49

the ratio of density to water density (10^3)

Front 50

the absolute pressure in a fluid due to gravity

Back 50

P = Po + pgh where Po = surface pressure

Front 51

gauge pressure

Back 51

Pg = absolute pressure - P(atm)

Front 52

Pascal's principle

Back 52

pressure is transmitted to every portion of a closed, incompressible fluid, so change in pressure = F1/A1 = F2/A2 and a displacement of volume in one area must equal the displacement in another (V = A1d1 = A2d2)

Front 53

Archimede's principle

Back 53

a body is buoyed up in fluid by a force equal to the weight of the fluid that it displaces; so the object will float as long as weight of displace fluid > object weight

Front 54

adhesion

Back 54

attractive force between liquid and molecules of another substance

Front 55

cohesion

Back 55

attractive force between molecules of same substance; causes surface tension because liquid have a net force pulling them down

Front 56

mass of a fluid flowing through a x-sectional area per second?

Back 56

area*velocity*density = constant

Front 57

is flow faster or slower through narrower passages?

Back 57

faster: v1A1 = v2A2 = constant

Front 58

Bernoulli's equation

Back 58

energy is conserved as fluid flows: P1 + (pv1^2)/2 + pgy1 = the same for 2 = constant; NOTE: if y1 = y2, then pressure decreases as velocity increases.

Front 59

viscosity

Back 59

the internal friction of a fluid; gas is less viscous than liquid because it is less dense. "nu" is measured in units of N*s/m^2 or dyne*2/cm^2 = poise and 10 poise = 1 N*s/m^2

Front 60

laminar flow

Back 60

thin layers of liquid sliding over one another

Front 61

laminar vs. turbulent flow?

Back 61

for fluid flowing through a tube of diameter D, velocity above a critical value, v(c), turns to turbulent flow: v(c) = (N*nu)/pD where N is Reynolds number and n is viscosity

Front 62

Young's modulus

Back 62

Y = (F/A) / (delta L / L) = stress/strain ; a large Y indicates a large stress produces only a small strain = a strong material

Front 63

stress vs. strain

Back 63

stress is the force pwer unit area where F is perpendicular to the area (i.e. pressure), and strain is the elongation per unit length (delta L / L)

Front 64

moduli

Back 64

different quantities that describe elasticity of a solid

Front 65

yield strength

Back 65

the point beyond which a material does not return to its original dimensions

Front 66

Shear modulus

Back 66

S = (F/A) / (x/h), describes shearing = a deforming stress where force is parallel to area

Front 67

Bulk modulus

Back 67

B = delta P / (delta V / V)

Front 68

electrostatic force

Back 68

the force between stationary charges

Front 69

charge of an electron

Back 69

1.60 E -19 C (the fundamental unit of charge)

Front 70

Coulomb's law

Back 70

force = k *q1*q2 / r^2 (magnitude of electrostatic force)

Front 71

electrostatic constant

Back 71

or Coulomb's constant, k = 8.99 E9 N*m^2/C^2 = 1/(4*pi*epsilon(o))

Front 72

permittivity of free space

Back 72

epsilon(o) = 8.85 E-12 C^2/N*m^2

Front 73

doubling the distance between two charges, changes the force?

Back 73

reduces the electrostatic force by 1/4, F is proportional to 1/r^2

Front 74

Electric field

Back 74

E=F/q in units of N/C = V/m, and where q is a positive test charge

Front 75

direction of an electric field

Back 75

toward negative, away from positive (therefore a negative charge feels a force opposite the field)

Front 76

electric potential at a point

Back 76

is the amount of work needed to move a positive charge from infinity to that point divided by the test charge: V = W/q in units of Volt = J/C

Front 77

1 V

Back 77

J/C

Front 78

electric potential of a point charge

Back 78

V = kq/r at a distance r from the point charge q

Front 79

potential difference

Back 79

V(b) - V(a) = W(ab) / q(o)

Front 80

electric potential across a cell membrane

Back 80

70-90 mV

Front 81

approximate pulse voltage of a pacemaker

Back 81

10 V

Front 82

electric potential energy

Back 82

U = qV = W (needed to move q from inifinity to that point)

Front 83

potential (at point P) of an electric dipole

Back 83

V = kq (1/r(1) - 1/r(2)) = sum of the two potentials

Front 84

potential at a large distance from a dipole?

Back 84

r(1)r(2) is approximately r^2 and r(2) - r(1) = d cos(theta) where theta is the angle between d and r (r is drawn at the midpoint, 1/2d)... so V = kqd * cos(theta) * 1/r^2

Front 85

dipole moment

Back 85

p = qd with units C*m and direction from negative to positive charges

Front 86

perpendicular bisector of a dipole

Back 86

when theta = 90, V =0 and the electric field along the line is E = kp / r^3 , and the field points opposite to p

Front 87

a dipole in a uniform external electric field

Back 87

experiences a torque, T = Fd*sin(theta) = qEd sin(theta) = pE*sin(theta) where E is the external electric field and theta is the angle between p and E

Front 88

during an isothermal process, how are P and V related?

Back 88

as P increases, V will decrease and vice versa

Front 89

if volume of a gas is constant, does gas do work?

Back 89

no, and delta T = PV/nR (from ideal gas law)

Front 90

units of magnetic field

Back 90

Tesla = N*s/m*C = 10^4 Gauss

Front 91

magnetic force

Back 91

F = qv cross B = qvB*sin(theta) where theta is the angle between qv and B

Front 92

right hand rule for magnetic force

Back 92

thumb in direction of q*v, fingers point in direction of B, and palm is in direction of magnetic force

Front 93

cross vector unit

Back 93

into the page

Front 94

work done by a magnetic force

Back 94

zero, because it is always perpendicular to velocity and the magnetic field

Front 95

a charge moving perpendicular to the magnetic field

Back 95

results in a circular motion with constant speed in the plane perpendicular to B

Front 96

radius of a charge in circular motion due to B

Back 96

r = mv/qB

Front 97

electric current

Back 97

flow of charge, I = delta q / delta t, with units of ampere

Front 98

1 A

Back 98

1 C/s

Front 99

direction of electric current

Back 99

from high to low potential, i.e. the direction of positive charge (opposite the actual flow of electrons from low to high potential)

Front 100

force on a current-carrying wire

Back 100

F = I*LBsin(theta) where L is the length of the wire, and theta is the angle between B and the wire (use RHR for direction)

Front 101

ferromagnetic

Back 101

e.g. Fe, Ni, and Co

Front 102

Curie Temperature

Back 102

temperature above which ferromagnetic material become paramagnetic; if Curie T is above room temp, the material is permanently magnetized

Front 103

direction of magnetic field lines

Back 103

from north to south poles (note that our north pole is actually a magnetic south pole)

Front 104

magnetic field due to an infinitely long straight wire

Back 104

at a perpendicular distance r, B = nu(o)*I / (2*pi*r), direction uses RHR (thumb in direction of current, and fingers curl around wire)

Front 105

permeability of free space

Back 105

nu(o) = 4*pi E-7 T*m/A = 1.26 E-6 T*m/A

Front 106

magnetic field at the center of a circular loop

Back 106

B = nu(o)*I / 2*r , magnetic field lines point into the page on one side and out on the other of the loop

Front 107

DC vs AC

Back 107

direct vs alternating current

Front 108

electromotive force

Back 108

emf = epsilon = voltage across the terminals of a cell when no current is flowing

Front 109

actual voltage supplied by a cell

Back 109

V = emf - I*R(internal)

Front 110

Ohm's Law

Back 110

voltage drop across a resistor is proportional to the current it carries, V = I*R

Front 111

units of resistance

Back 111

ohm

Front 112

resistance of a conductor

Back 112

inreases with increased length, decreased cross-sectional area

Front 113

resistivity

Back 113

the intrinsic resistance to current flow of a material, p, where R = p*L/A

Front 114

resistance and temperature

Back 114

are proportional in most materials, except glass, pure silicon, and most semiconductors

Front 115

power dissipated by a resistor

Back 115

P = I*V where V is the potential across the resistor, = I^2 *R = V^2/R

Front 116

Kirchhoff's Laws

Back 116

junction rule (currents in = out, due to conservation of electric charge) and loop rule (energy is conserved in complete loop)

Front 117

resistance, series vs. parallel

Back 117

adds in series, 1/R(parallel) = 1/R(1) +1/R(2) ... because parallel arrangment increases the cross sectional area of a conductor, i.e. increases the paths by which current can flow

Front 118

voltage across parallel resistors

Back 118

each have same voltage drop

Front 119

when n identical resistors are wired in parallel, R =

Back 119

R(parallel) = R/n

Front 120

STP

Back 120

standard temperature and pressure (for gases), 273 K and 1 atm

Front 121

an ideal gas

Back 121

a gas that experiences no intermolecular forces and whose particles occupy no volume

Front 122

conditions under which gases behave like ideal gases

Back 122

low pressures, high temperatures

Front 123

Ideal Gas Law

Back 123

PV = nRT

Front 124

ideal gas constant

Back 124

R = 8.31 J/K*mol

Front 125

effect of changing T on internal energy of a monoatomic ideal gas

Back 125

delta U = 3/2 * nR * deltaT

Front 126

an ideal gas and internal energy

Back 126

internal energy is completely dependent on temperature; so if no deltaT, no deltaU

Front 127

sign of Q for heat added to a system

Back 127

Q>0 , positive

Front 128

sign of W for work done by the gas

Back 128

W>0, positive when the gas loses energy; if work is done ON the gas, then W is negative

Front 129

change in internal energy for a gas

Back 129

deltaU = Q - W

Front 130

work done by a gas during a thermodynamic process

Back 130

equal to the area enclosed by its P-V curve

Front 131

decreased volume due to...

Back 131

work done ON the gas, therefore area under P-V curve is a negative quantity

Front 132

cyclic processes

Back 132

no change in internal energy, but work done by gas = enclosed area

Front 133

for an isothermal process, internal energy...

Back 133

does not change (for an ideal gas) and Q = W; also P and V are inversely related

Front 134

temperature change if volume increases at constant P

Back 134

T increases

Front 135

capacitor

Back 135

stores charge

Front 136

capacitance

Back 136

C = Q/V where Q is the charge on one plage and V is the potential difference, in units of farads; dependent on the geometry of the two conducting surfaces

Front 137

1 F

Back 137

C/V = also the charge on a mole of elementary charges = 9.65 E4 C

Front 138

capacitance of a parallel plate capacitor

Back 138

C = epsilon(o)*A/d where A is the area of overlap of the two plates, d is the distance between them, and epsilon(o) is the permittivity of free space

Front 139

electric field between two plates of a parallel plate capacitor

Back 139

E = V/d, pointing toward the negative plate

Front 140

dialectrics

Back 140

an insulator (e.g. glass, plastic, certain metal oxides) placed between two plates to lower the voltage and "make room" for more charge, effectively increasing the capacitance

Front 141

change in capacitance due to a dialectric

Back 141

C' = KC where K is the dialectric constant

Front 142

capacitors in parallel vs series

Back 142

add in parallel (each have same voltage), 1/C(s) = 1/C(1) + 1/C(2) ... and total voltage is the sum of individual voltages

Front 143

how to arrange capacitors to minimize C?

Back 143

place in series

Front 144

instantaneous current in AC

Back 144

I = I(max)*sin(2*pi*f*t) = I(max)*sin(omega*t)

Front 145

angular frequency

Back 145

omega=2*pi*f

Front 146

ordinary house current

Back 146

AC with frequency of 60 Hz

Front 147

average power

Back 147

P(rms) = I(rms)^2 *R = I(max)^2 *R*1/2

Front 148

average current of AC

Back 148

is zero, but the root mean sqare, I(rms) = I(max)/sqrt2

Front 149

potential of AC

Back 149

V(rms) = V(max)/sqrt2

Front 150

simple harmonic motion

Back 150

oscillation about an equilibrium point (where net force = zero), and subject to a linear restoring force

Front 151

linear restoring force

Back 151

always directed toward the equilibrium point, with a magnitude directly proportional to the displacement from the equilibrium (note - acceleration is therefore also proportional to displacement)

Front 152

Hooke's Law

Back 152

F = -kx where k is the spring constant (negative sign indicates that the force acts opposite to direction of displacement)

Front 153

angular frequency (of an oscillating spring)

Back 153

w = sqrt(k/m)

Front 154

acceleration (of an oscillating spring)

Back 154

a = -(w^2)x

Front 155

larger spring constant indicates..

Back 155

a stronger, stiffer spring

Front 156

for a pendulum, "k" is

Back 156

k = mg/L

Front 157

amplitude of a pendulum swing

Back 157

is its max displacement, where x = x(max) cos(wt), if x(max) occurs at t=0

Front 158

angular frequency

Back 158

w = 2*pi*f = 2*pi / T

Front 159

potential energy of a pendulum

Back 159

is gravitational potential energy = mgh

Front 160

potential energy of a spring

Back 160

U = 1/2 kx^2 (note that U=0 at equilibrium, which is where K=Kmax)

Front 161

frequency and amplitude in SHM?

Back 161

frequency and period are independt of amplitude in simple harmonic motion

Front 162

angular frequency (of a pendulum)

Back 162

w = sqrt (g/L), where L is the length of the string

Front 163

where does max acceleration occur (for SHM)?

Back 163

at maximum force, which is at maximum displacement

Front 164

constructive vs. destructive interference

Back 164

add amplitude (waves are in phase) vs. waves are 180* out of phase

Front 165

speed of a wave

Back 165

v = f*lambda = w/k = lambda/T, where k = wave number (also is the speed at which a crest or trough progagates through space)

Front 166

wave number

Back 166

k = 2*pi / lambda (note: lambda is the distance from one max to the next)

Front 167

oscillations of a wave

Back 167

y = y(max) * sin(kx - wt) where k is the wave number and y(max) is the amplitude

Front 168

longitudinal waves

Back 168

waves that have oscillations (or vibrations) that are parallel to their direction of travel; examples include sound waves and pressure waves

Front 169

transverse waves

Back 169

a moving wave that has oscillations occuring perpendicular to the direction of energy transfer; examples include an oscillating string and electromagnetic waves

Front 170

standing waves

Back 170

waves that stay in one position; this can be due either to the medium moving in the opposite direction to that of wave propagation, or of two waves moving in opposite directions leading to interference (if the latter and the amplitudes are equal, then there is on average no net propagation of energy)

Front 171

nodes

Back 171

points in a standing wave that remain at rest, i.e. have minimal amplitude (y=0)

Front 172

antinodes

Back 172

points in a standing wave that fluctuate with maximum amplitude. Occurs at points midway between nodes.

Front 173

forced oscillation

Back 173

a frequency is produced equal to the frequency of force, which is not a normal mode of vibration. The amplitude of motion will be small unless the frequency of F(applied) is close the natural frequency of the system

Front 174

resonance

Back 174

occurs when the frequency of the F(applied) is equal to a natural frequency of the system, producing a maximum amplitude of oscillation.

Front 175

resonance f of a pendulum

Back 175

f(res) = sqrt(g/L) / 2*pi = w / (2*pi)

Front 176

resonance f of a spring

Back 176

f(res) = sqrt(k/m) / 2*pi = w / (2*pi)

Front 177

sound

Back 177

a longitudinal wave produced by a mechanical disturbance propagated through a deformable medium (i.e, cannot be transmitted through a vacuum).

Front 178

speed of sound, differences in medium

Back 178

faster in solid > liquid > gas

Front 179

frequency of audible waves for humans

Back 179

f = 20 - 20,000 Hz

Front 180

infrasonic vs. ultrasonic waves

Back 180

are <20 Hz vs. > 20,000 Hz

Front 181

speed of sound in air, 0*C

Back 181

331 m/s

Front 182

intensity of sound

Back 182

I = average rate per unit area at which energy is transported across a perpendicular surface by the wave = power/area; in units of Watts/m^2

Front 183

power of sound, carried across a surface area (e.g., an eardrum)

Back 183

P = IA, where I is (uniformly distributed) intensity and A is the surface area

Front 184

sound level

Back 184

beta = 10 log [I/I(o)], where I(o) is a reference intensity of 10^-12 W/m^2; beta is measured in decibels

Front 185

faintest sound a human can hear

Back 185

I(o) = 10^-12 W/m^2

Front 186

pitch

Back 186

the sensation of sound that enables one to classify the frequency of a note. It is a subjective quantity and can't be measured with instruments.

Front 187

beats

Back 187

a periodic variation in loudness created by two waves of nearly equal frequency adding together; beat frequency = |f(1) - f(2)|

Front 188

instruments and wave length

Back 188

wavelength is fixed since the standing wave corresponds to a particular note and the length of the instrument does not change; f = v/lambda

Front 189

wave velocity and temperature

Back 189

wave velocity is proportional to the sqrt of absolute temperature... so as T decreases, velocity decreases, and the frequency (or pitch) of the sound also decreases

Front 190

Doppler effect

Back 190

perceived and emitted frequencies of sound differ; if the source and detector are moving toward eachother, then the observed frequency > actual f. The opposite occurs if they are moving away from eachother.

Front 191

observed frequency in relation to actual

Back 191

f(observed) = f *[(v + v(d)) / (v - v(s))], where v is the speed of sound in the medium, v(d) is speed of detector relative to the medium, and v(s) is the speed of source relative to the medium. If the sources are moving away from each other, you must flip the signs in the equation.

Front 192

source and detector move at same velocity - is there a Doppler effect?

Back 192

no

Front 193

possible frequencies of a string attached at both ends

Back 193

f = (nv) / (2L), derived from the fact that at length L, a string can support standing waves of lambda = 2L/n

Front 194

fundamental frequency

Back 194

or first harmonic; the lowest possible frequency of a string, f = v / 2L

Front 195

first overtone

Back 195

or second harmonic, the frequency at n=2, so f = v / L

Front 196

harmonic series

Back 196

all possible frequencies that a string can support

Front 197

higher harmonics

Back 197

have a lower wavelength, but higher frequency... all have the same wave speed

Front 198

nodes and wavelengths in a string

Back 198

for the harmonic n, there are n half wavelengths that fit exactly along the length of the string; and there are n+1 nodes

Front 199

antinodes and pipes

Back 199

antinodes occur at the open ends

Front 200

for a closed pipe, allowed frequencies are?

Back 200

f = nv / 4L where n is odd integers only; L = n*lambda / 4

Front 201

how much has intensity increased if the sound is increased 20 dB?

Back 201

a factor of 100

Front 202

radio wavelength

Back 202

10^9 m - 1m

Front 203

microwave wavelength

Back 203

1 m - 1 mm

Front 204

infrared wavelength

Back 204

1 mm - 700 nm

Front 205

visible light wavelength

Back 205

700 - 400 nm

Front 206

ultraviolet wavelength

Back 206

400 - 50 nm

Front 207

x-ray wavelength

Back 207

50 - 10^-2 nm

Front 208

gamma ray wavelength

Back 208

<10^-2 nm

Front 209

electromagnetic spectrum by decreasing wavelength

Back 209

radio > microwave > infrared > visible light > ultraviolet > xray > gamma rays

Front 210

violet vs. red wavelengths

Back 210

400 vs. 700 nm

Front 211

the color white

Back 211

is light that contains all colors in equal intensity

Front 212

speed of light

Back 212

the velocity of all electromagnetic waves in a vacuum (and to a first approximation in air), c = 3.00 E8 m/s

Front 213

rectilinear propagation

Back 213

light travels in a straight line through a single homogenous medium

Front 214

reflection

Back 214

rebounding of incident light waves at the boundary of a medium (even if medium is transparent); the angle of rebound is equal to the angle of incident relative to the normal line

Front 215

plane mirrors

Back 215

produce virtual images; parallel incident rays remain parallel after refelction from a plane mirror. The light appears to be coming from the position fo the image but does not converge there.

Front 216

spherical mirrors

Back 216

can be concave (converging, positive f) or convex (diverging, negative f). They have a center of curvature, C and a radius of curvature.

Front 217

focal length

Back 217

f = the distance between the focal point and the mirror. For all spherical mirrors, f = r/2

Front 218

radius of curvature

Back 218

r = distance between the center of curvature and the mirror = 2f

Front 219

equation for mirrors

Back 219

1/o + 1/i = 1/f = 2/r, where o is the distance between object and mirror, and i is the distance of the image from the mirror

Front 220

real vs. virtual image

Back 220

i is positive (image is in front of the mirro) vs. i is negative (and image is behind the mirror)

Front 221

equation for plane mirrors

Back 221

r = f = infinity, so 1/o + 1/i = zero... or i = -o, which means that the image is virtual

Front 222

magnification

Back 222

m = the ratio of image to object height = -i / o; a negative m signifies an inverted image, while positive is upright; |m| < 1 is a reduced image

Front 223

a ray that strikes a converging mirror parrallel to the horizontal...

Back 223

is reflected through the focal point

Front 224

a ray that passes through the focal point before reaching a convergin mirror...

Back 224

is reflectred parallel to the horizontal

Front 225

a ray that strikes where the normal passes through a converging mirror...

Back 225

is reflected at same angle to the normal

Front 226

one diverging mirror results in...

Back 226

one virtual, erect image

Front 227

one converging mirror results in...

Back 227

real, inverted image (o > f); or no image (o = f = light rays are reflected parallel to eachother and never converge); or a virtual, erect image (o < f)

Front 228

concave vs. convex (in terms of r and f)

Back 228

positive r and f, vs. negative r and f

Front 229

Snell's Law

Back 229

for refracted rays of light: n1*sin(theta1) = n2*sin(theta2), where n is the index of refraction of a medium, and theta is the angle of incident light with respect to the normal line crossing the barrier between the two mediums

Front 230

index of refraction

Back 230

n = c / v, where c is the speed of light in a vacuum and v is the speed of light in the medium (n is close to 1 for air)

Front 231

if n2 > n1

Back 231

light bends toward the normal, i.e. theta2 < theta1

Front 232

total internal reflection

Back 232

a condition where all the light incident on a boundary is reflected back into the original material, a result of any angle of incidence > the critical angle

Front 233

critical angle

Back 233

sin(theta(c)) = n2/n1; theta(c) occurs where theta1 results in theta2 = 90*... can only occur if light is passing from a higher to lower index of refraction, n1 > n2

Front 234

thin spherical lenses

Back 234

lenses have two focal point and two focal lengths; a thin lens is one whose thickness can be neglected, so F1 = F2

Front 235

converging vs. diverging lens thickness

Back 235

always thicker at the center vs. thinner at center

Front 236

converging lens and parallel rays

Back 236

converging lens causes parallel rays to converge at the focal point, and rays from the focal point to emerge parallel

Front 237

thick spherical lens

Back 237

if thickness cannot be neglected, focal length is related to curvature of the lens surface and refractive index by Lensmaker's equation

Front 238

Lensmaker's equation

Back 238

1/f = (n-1) (1/r1 - 1/r2)

Front 239

power of a lens

Back 239

P = 1/f; measured in units of dipoters when f is in meters; positive for converging, and negative for diverging lens

Front 240

lenses in contact

Back 240

a series of lenses with negligible distances between them (e.g., the eye); they behave as a single lens with equivalent focal length: 1/f = 1/f1 + 1/f2 + 1/f3... and P = P1 + P2 + P3...

Front 241

lenses not in contact

Back 241

the image of one lens is used to make the object of the next; e.g., microscopes, telescopes; magnification, m = m1 * m2 * m3...

Front 242

dispersion

Back 242

occurs when the speed of the wave varies with wavelength, for example, the splitting of white light through a prism. It occurs b/c one color of light experiences a greater refractive index than another, so it is bent differently

Front 243

diffraction

Back 243

the spreading out of light as it passes through a narrow opening (where narrow is on the order of wavelengths). It is the interference of an infinite number of waves, where each point along the slit acts as a wave source.

Front 244

zeroth fringe

Back 244

the largest bright fringe, in the center of a line of diffracted light

Front 245

location of dark fringes

Back 245

sin(theta) = n*lambda, where n is a positive integer and theta is the angle between the line drawn from center of lens to a dark fringe and the line perpendicular to the screen

Front 246

monochromatic light

Back 246

light of just one wavelength

Front 247

coherent light

Back 247

light waves whose phase difference does not change with time

Front 248

light intensity on a screen due to single-slit diffraction

Back 248

are due to constructive interference betweeen two light waves

Front 249

maxima vs. minima on a screen

Back 249

maxima: d*sin(theta) = m*lambda; minima: d*sin(theta) = (m+1/2)*lambda, where m is an integer indication the order, d is the distance between slits

Front 250

for small angles, sin(theta) equals?

Back 250

sin(theta) = tan(theta

Front 251

plane polarized light

Back 251

light in which the electric fields of all the waves are oriented in the same direction. Magnetic fields are also parallel, but convention dictates that the plane of the electric field identifies the plane of polarization

Front 252

unpolarized light

Back 252

light with randomly oriented electric fields (e.g., sunlight)

Front 253

polarizers

Back 253

only allow light whose electric field is pointed in a particular direction to pass

Front 254

blackbody

Back 254

an ideal radiator (which is also an ideal absorber, thus appearing totally black if at a lower temperature than its surroundings); can be approximated by radiation produced in a cavity with a hot object (= cavity radiation)

Front 255

Planck's constant

Back 255

h = 6.63 E-34 J*s = 4.14 E-15 eV*s

Front 256

Wien's displacement law

Back 256

lambda(peak)*T = constant = 2.90 E-3 m*K, where lambda(peak) is the wavelength at which maximum energy is emitted

Front 257

Stefan-Boltzmann Law

Back 257

total energy being emitted per unit area per second is proportional to the 4th power of the absolute temperature: E = alpha*T^4, where alpha is the S-B constant = 5.67 E-8 J/s*m^2*K^4

Front 258

photoelectric effect

Back 258

light of a sufficiently high frequency (e.g., blue or UV) is incident on a metal ion in a vacuum, causing the metal to emit an electron. The threshold frequency is dependent on the type of metal.

Front 259

energy of a photon

Back 259

E = hf, where h is Planck's constant and f is the frequency of the light... note that energy is proportional to frequency, and inversely proportional to wavelength

Front 260

if the frequency of incident light is much greater than threshold frequency of the metal...

Back 260

the excess energy is converted to kinetic energy in the electron

Front 261

max kinetic energy of an emitted electron

Back 261

KEmax = hf - W, where W is the work function of the metal = minimum energy needed to eject an e-

Front 262

minimum energy needed to eject an electron

Back 262

W = h*threshold frequency

Front 263

current of electrons produced by f > f(threshold)

Back 263

is directly proportional to the intensity of the light beam

Front 264

ionization

Back 264

the electron reaches an energy of at least 0 eV and is unbound (free from the electrostatic/Coulombic pull of the nucleus)

Front 265

fluorescence

Back 265

process in which certain substances emit visible light when excited by other radiation (usually UV). By returning to ground in two+ states, each step down emits a photon of lower frequency whose wavelength may fall in the visible portion of the spectrum

Front 266

binding energy

Back 266

amount of energy required to break up a given nucleus into its constituent protons and neutrons

Front 267

energy and mass

Back 267

E = m*c^2; the constituent parts of a nucleus have greater mass apart than they do together because of the interconvertibility of mass and energy

Front 268

mass defect

Back 268

the difference in mass between a nucleus and the sum of its constituent parts; a result of matter being converted to energy

Front 269

nucleus vs. atom radius

Back 269

radius of a nucleus is about 100,000 times smaller

Front 270

radionuclide

Back 270

a radioactive isotope

Front 271

deuteron

Back 271

H (A = 2), of deuterium

Front 272

triton

Back 272

H (A = 3), of tritium

Front 273

greatest binding energy per nucleon

Back 273

peaks at iron - implies that iron is the most stable atom. In general, intermediate-sized nuclei are the most stable

Front 274

fusion

Back 274

combine small nuclei to large (e.g., in the sun, 4H yield 1He

Front 275

fission

Back 275

split by large into small nuclei. Can be induced in some isotopes by absorption of a low energy neutron; if neutrons are released, these may cause further fission (a chain reaction).

Front 276

radioactive decay

Back 276

a naturally occurring spontaneous decay of certain nuclei accompanied by the emission of specific particles

Front 277

alpha decay

Back 277

emits an alpha particle (He-4); b/c it is doubly charged and very massive, it interacts with matter well and does not penetrate shielding very far.

Front 278

beta decay

Back 278

emission of a beta particle - an electron or positron - from a neutron or proton decaying in the nucleus.

Front 279

emission of an electron

Back 279

result of a neutron decaying into a proton and a beta-particle (or antineutrino); mass number stays the same, but atomic number increases by 1.

Front 280

emission of a positron

Back 280

result of a proton decaying into a neutron and a positron; mass number stays the same, but atomic number decreases by 1.

Front 281

antineutrino

Back 281

or beta-particle, electron

Front 282

gamma decay

Back 282

emits a gamma particle, which are high energy photons; they carry no charge, but decrease the energy of the emitting nucleus

Front 283

electron capture

Back 283

some unstable radionuclides can capture inner (K or L shell) electrons to combine with a proton and form a neutron; mass number remains the same, but atomic number decreases by 1.

Front 284

amount of sample left of radioactive sample

Back 284

(1/2)^n where n is the number of half lives

Front 285

exponential decay

Back 285

rate of decay depends on the sample size = - lambda*n, where lambda is the decay constant, and n is the sample size

Front 286

amount of sample left due to exponential decay

Back 286

n = n(o)*e^(-lambda*t), where lambda = (ln2) / half-life = 0.693 / t(1/2)