# Shared Flashcard Set

## Details

Physics Exam 3
University of Iowa
53
Physics
11/02/2018

Term
 Electromotive force (emf)
Definition
 maximum potential difference across the terminals
Term
 Electric Current
Definition
 amount of charge per unit time that passes through a surface that is perpendicular to the motion of the charges
Term
 Ampere (A)
Definition
 one coulomb per second
Term
 Direct current (dc)
Definition
 if the charges move around the circuit in the same direction at all times
Term
 Alternating current (ac)
Definition
 if the charges move one way and then the opposite way
Term
 Convectional current
Definition
 hypothetical flow of positive charges that would have the same effect in the circuit as the movement of negative charges that actually does occur
Term
 Resistance (R)
Definition
 ratio of the voltage (V) applied across a piece of material to the current I through the material
Term
 Ohm's Law Equation
Definition
 V/I = R -or- V = IR
Term
 Ohm's Law Definition
Definition
 voltage applied across a piece of material and current through the material
Term
 Resistor
Definition
 the extent that a wire or an electrical device offers resistance to electrical flow
Term
 What is Ohm's Law important for?
Definition
 important for circuits
Term
 What side of the battery has higher potential?
Definition
 the positive side
Term
 What will a perfect battery equal?
Definition
 The emf
Term
Definition
 The current will be the same everywhere in the circuit
Term
 Series resistors questions
Definition
 R_s = R_1 + R_2 + R_3 etc.
Term
 What does parallel wiring mean?
Definition
 the voltage will be applied across each device
Term
 Series potential
Definition
 potential drop across each resistor is different in general (V = V_1 + V_2)
Term
 Parallel potential
Definition
 V_1, V_2these are equal
Term
 Resistors in a series
Definition
 the same current goes through each of the resistors in series, but the potential drop across each resistor is different
Term
 Resistors in parallel
Definition
 the current splits into the resistors in parallel, so the currents are different, but the potential drop across each resistor is the same
Term
 When two resistors are connected in parallel what happens?
Definition
 they draw more current than does either resistor alone
Term
 Reminder for math in parallel resistance
Definition
 add the inverses and then take the inverse
Term
 Electric power
Definition
 a current in a circuit as a result of a voltage then P = IV
Term
 What is the SI unit of power?
Definition
 watt (W)
Term
 Magnetic field
Definition
 the magnitude of the magnetic field B at any point in space
Term
 Conditions for a charge to experience a magnetic force
Definition
 1.) charge must be moving2.) velocity of the charge must have a component that is perpendicular to the direction of the magnetic field
Term
 Magnitude of the force
Definition
 depends on component of velocity perpendicular to the magnetic field B
Term
 What do the fingers of the right hand rule represent?
Definition
 Thumb: direction of forcePointer: direction of currentMiddle: direction of magnetic field
Term
 What symbol represents out of the page?
Definition
 dot
Term
 What symbol represents into the page?
Definition
 an X
Term
 Force changes direction as ______ changes direction.
Definition
 velocity
Term
 Right hand rule #2
Definition
 Thumb is now the direction of the convectional currentfinger tips are the direction of the magnetic field
Term
 The magnetic field will be stronger _____ to the magnet.
Definition
 closer
Term
 Lenz's Law
Definition
 induced emf resulting from a changing magnetic flux has a polarity that leads to an induced current whose direction is such that the induced magnetic field opposes the original flux change
Term
 Transformer
Definition
 device for increasing or decreasing an ac voltage
Term
 What are the two different types of waves?
Definition
 transverse and longitudinal
Term
 Are water waves transverse or longitudinal?
Definition
 both
Term
 Periodic waves
Definition
 cycles or patterns that are produced over and over again by the source
Term
 Cycle
Definition
 one complete wave
Term
 Amplitude
Definition
 maximum excursion of a particle of the medium from the particles undisturbed position
Term
 Wavelength
Definition
 horizontal length of one cycle of the wave
Term
 Period
Definition
 time required for one complete cycle
Term
 Frequency
Definition
 related to the period and has units of Hz (cycles per second)
Term
 The distance between adjacent condensations is equal to the wavelength of the ______ ______.
Definition
 sound wave
Term
 Pure tone
Definition
 sounds with a single frequency
Term
 Pitch
Definition
 frequency in terms of the subjective quality
Term
 Loudness
Definition
 the pressure amplitude of the wave
Term
 Doppler effect
Definition
 change in frequency or pitch of the sound detected by an observer because the sound source and the observer have different velocities with respect to the medium of sound propogation
Term
 Linear Superposition
Definition
 two or more waves are present simultaneously at the same place, the resultant disturbance is the sum of the disturbances from the individual waves
Term
 Constructive interference
Definition
 exactly in phase
Term
 Destructive interference
Definition
 exactly out of phase
Term
 Beat frequency
Definition
 the difference between the two sound frequency
Term
 The principle of linear superposition
Definition
 when two or more waves are present simultaneously at the same place, the resultant disturbance is the sum of the disturbances from the individual waves
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