Physics Flashcards
A smaller standard deviation means that data is __ to the mean.
closer
A higher standard deviation means that the data is __ from the mean.
more dispersed
Outliers can be measured by either 1.5 x IQR or being __ number of standard deviations below or above the mean.
3
Current, a measure of positive charge, is measured in amperes which can be described as __
C/s
Voltage, a measure of potential difference between 2 points, is measured in volts which can be described as __
J/c
Emf, a measure of potential difference of a voltage source, is measured in volts which can be described as __
J/c
Conductivity, a reciprocal measure of resistance permissiveness to current is measured in Siemens which can be described as __
S
Kirchoff’s Rules for conservation suggest that
Current (I) into = Current (I) leaving and Voltage Source= Voltage Drop
I=Q/ deltaT looks like a melted ice cream cone and is used to measure__
Conductivity ; where I = current , Q= amount of charge and delta T is time
Resistance, defined as opposition to flow or movement of charge, can be calculated using the following equation__
R= resistivity * length / cross-sectional area
Resistivity is an intrinsic proprerty and measured in the following units
ohms * m
If length increases by 2x then resistance would _
also double
If surface area increases then resistance will __
decrease
If temperature increases then resistance will _
increase
Ohm’s law relates Voltage, Current and Power. What is the equation associated with Ohm’s law?
V= IR
Resistors in a series can be (pick one: added or 1/resistor) and Rs (pick one: increases or decreases) with more resistors
added (R1+ R2 +…Rn) ; increases
Resistors in parallel can be calculated using 1/R1 + 1/R2 … + 1 /Rn. With more resistors what can we expect to happen?
Rp decreases
Capacitors, like defibrillators, hold charge at a certain voltage that can be released. How do we calculate capacitance (hint: also looks like drippy ice cream cone)?
C= Q/ V where capacitance is measured in farads but mostly microfarads = 1 x 10^-6 farads
In order to calculate the electric field of a parallel plate capacitor we can use the following equation:
E= V/d
Capacitors are said to be caked with charge which coincidentally is why we can set up an equation in the following way:
C= AKE0 / d where k can never be <1 and capacitance increases as voltage decreases
For capacitors in a series, unlike resistors, Cs will __ with more capacitors. We __ capacitor in a series to calculate Cs.
decreases ; 1/C1 + 1/C2 .. + 1/Cn
For capacitors in parallel, unlike resistors, Cp will __ with more capacitors. We __ capacitor in a parallel to calculate Cp.
increases; C1 + C2 … + Cn
An ammeter measures __ and is placed __ . It has an ideal resistance of 0.
current ; in series
A voltmeter measures __ and is placed __ . It has an ideal resistance of infinity.
Potential difference/voltage ; parallel with circuit
An ohmmeter measures __ and is placed __ . It has an ideal resistance of 0.
resistance ; 2 points in a series with a circuit element
Types of electromagnetic radiation from longest to shortest
Radio Microwave Infrared Visible (700-400 nm) UV Xray Gamma Ray
Properties of electromagnetic waves
1) transverse due to electrical and magnetic vectors being perpendicular to the direction of propagation
2) vary in frequency and wavelength
3) in a vacuum travels at speed of light C = 3 x 10^ 8 ms (C= frequency x wavelength)
ROYGBV Red can be expected to be at __ nm whereas violet would be at __
700 ; 400
A red colored object absorbs all other colors of light except for __ which it instead reflects.
red (itself)
Blackbody
all wavelengths of light, appears completely black if lower temperature than surroundings
White
light with all colors and equal intensity
If light speed decreases you get more __
n is the ratio of the speed of light in a vacuum / speed of light in whatever substance you have light going into.
So n = 1, means it’s a vacuum. n can never be < 0, because that would light is traveling faster than c.
Refraction = bending and the shortest distance between two points is a straight line. So if light speed decreases, you get more bending and vice versa.
Snell’s Law (Index of Refraction)
index of refraction = speed of light vacuum /speed of light in medium
Snell’s Law: as light enters a medium with a high index of refraction it bends __
normal
Snell’s Law: as light enters a medium with a low index of refraction it bends __
away
Relation of index of refraction to the angle of incidence / refraction (n1 sin theta1) = (n2 sin theta2)
the index of refraction is inversely related to the angle of incidence/refraction. The bigger the index of refraction, the small the angle of incidence/refraction is
Plane Polarized
light rays have electric fields of parallel orientation
Circularly Polarized
all light rays have electric field of equal intensity but constantly rotating direction
exposing unpolarized light to special pigments or filters
Single Slit
wide arc
Double Slit (Young)
contains fringes
Split Lens
multiple slits –> displacement
waves –> interference
constructive -_> brighter , maxima
destructive –> dark, minima
Diffraction Fringes (i.e. double slit consequence)
caused by constructive and destructive interference between light rays
Plane Mirrors
real : light converges at position of the image
virtual : light only appears to be coming from the position of the image but does not converge there
Spherical Mirrors
1) concave: like looking into a cave / converging
2) convex: diverging
f= focal length = r / 2
Spherical Mirrors: m= -i/o
i> o real image
i< o virtual image
Lenses (Power)
power = 1/ focal length
+ indicates converging (farsightedness)
- indicates diverging (nearsightedness)
Multi Lens System
1/ f = 1/f1 + 1/f2 + …
Power (lenses)
P= P1 + P1 + P3…
Lens Magnification
m= m1 x m2 x m3…
Spherical Aberration
blurred periphery
Chromatic Aberration
see rainbow when wearing glasses
Convex mirror
Light rays diverge
Image is upright and virtual
Image appears smaller
f<0, o>0, i<0
Concave Mirror
Light rays converge
Image is inverted and real
Image appears larger
f>0, o>0, i>0
Convex Lens
Light rays converge
Image is inverted and real
f>0, o>0, i>0
Concave Lens
Light rays diverge
Image is upright and virtual
f<0, o>0, i<0
Total internal reflection
occurs when the angle of incidence is greater than the critical angle for a given transition between materials. For a light ray traveling from air into water, for example, the critical angle is 48.5° If a ray of light angle of incidence is 50° (measured from the perpendicular), it will be completely reflected. We can use Snell’s law to find the critical angle.
Fg= density x Vg
weight of any volume of known density subst. density x volume & acceleration
SG= density / 1 g/cm3
specific gravity is just density
Pascal’s Law:
Pressure = Force / Acceleration with the SI unit of Pa. 1 x 10^5 Pa = __ mmHg and __ atm.
760 and 1
larger area and larger force
Absolute Pressure
ambient pressure + (density * acceleration due to gravity * depth)
Hydraulic Systems
near incompressibility generates mechanical advantage by allowing us to magnify input by factor EQUAL TO RATIO OF THE CROSS SECTIONAL AREA OF THE LARGER PISTON TO SMALLER PISTON
Archimedes Principle of Buoyancy
object wholly or partially immersed in fluid will be buoyed up by a force that is equal to the weight of the fluid displaced
Archimedes Principle of Buoyancy (equation)
Fbuoy= densityfluid * Volumefluiddisplaced g
or volume of fluid submerged
Cohesion
between molecules with same properties ; surface tension
Adhesion
attractive force a liquid feels towards molecules of other substances
Viscosity
resistance to fluid flow
higher viscosity the higher the viscous drag
assumed negligible for Bernoulli’s
SI unit = Pa * s = N *s / m^2
Laminar Flow
smooth, orderly and layer closest to the walls of pipe flow slower than interior
Poiseuille’s Equation indicates that radius and pressure gradient are inverse exponential to the 4th power (equation)
Q = pi *r^4 *change in P / 8 * viscosity * L
Turbulent Flow
rough and forms eddies (swirls of fluid)
when speed of fluid exceeds critical speed
flow speed at wall = 0 ; increases then irregular and turbulent
cannot apply Bernoulli
Streamlines
flow rate constant for closed system and independent of changes to cross sectional area
constant flow rate still linear speed changes -> linear speed increases as the cross sectional area decreases
Bernoulli
less movement = greater static pressure
more movement = lesser static pressure
Bernoulli Equation
Pressure Energy + KE per unit volume + PE per unit volume = “” after
Venturi
as cross sectional area gets smaller the linear speed increases and the dynamic pressure increases which leads ultimately to lower absolute pressure which makes column 2 lower
Cannot use continuity equation for human circulation
because of pulse, vessels and elastic pressure gradient
but Poiseuille’s can be used for isolated segments
