Physics II Final Exam Review (Charge through Frames of Reference)

Inductor

A circuit element that stores energy in a magnetic field when current flows and resists changes in current

Inductance

A measure of how much an inductor opposes changes in current (unit: Henry)

Inductor in circuits

Slows changes in current and stores/releases energy

LC Oscillator

A circuit with an inductor and capacitor that oscillates energy between electric and magnetic forms

RLC Oscillator

An LC circuit with resistance where oscillations decrease over time due to energy loss

Driving frequency

The frequency of an external AC source applied to a circuit

Resonance frequency

The frequency where inductive and capacitive effects cancel producing maximum current

Reactance

Opposition to AC current caused by capacitors or inductors that depends on frequency

Impedance

Total opposition to AC current combining resistance and reactance

Capacitor in AC

Opposes low-frequency signals strongly and allows high-frequency signals more easily

Inductor in AC

Opposes high-frequency signals strongly and allows low-frequency signals more easily

Resistor in AC

Behaves the same regardless of frequency

Resonance in AC

Condition where impedance is minimized and current is maximized

Transformer

A device that changes voltage using magnetic induction commonly used in power transmission

Electromagnetic wave

A wave consisting of oscillating electric and magnetic fields

Electric and magnetic field relationship

Fields are perpendicular to each other and to the direction of wave motion

Wave speed

Electromagnetic waves travel at the speed of light

Intensity

Power per unit area carried by a wave

Power vs intensity

Power is total energy per time while intensity is power spread over an area

Intensity vs distance

Intensity decreases with the square of the distance from the source

Radiation pressure

Force exerted by light when it strikes a surface

Polarization

Restriction of light waves to a single direction of oscillation

Polarized light

Light oscillating in one direction

Unpolarized light

Light oscillating in multiple directions

Polarizing filters

Allow only light of a certain orientation to pass through reducing intensity

Reflection

Light bouncing off a surface

Refraction

Light bending when entering a different medium

Chromatic dispersion

Different wavelengths bend differently causing separation of colors

Total internal reflection

Light completely reflects inside a medium at certain angles

Polarization by reflection

Reflected light becomes partially polarized

Postulates of relativity

The laws of physics are the same in all inertial frames and the speed of light is constant

Inertial frame

A frame of reference moving at constant velocity

Proper time (t₀)

Time measured in the rest frame of an event

Proper length (L₀)

Length measured in the object’s rest frame

Time dilation

Moving clocks appear to run slower

Length contraction

Moving objects appear shorter in the direction of motion

Mass increase

Moving objects appear to have greater mass

Lorentz transform

Equations that relate space and time measurements between moving frames

Current

Flow of electric charge

Current density

Current per unit cross-sectional area

Drift velocity

Average velocity of charge carriers in a conductor

Resistivity

Material property that determines how strongly it resists current

Resistance

Opposition to current flow in a circuit

Ohm’s law

Voltage is proportional to current

Ohmic device

A device that follows Ohm’s law

Non-ohmic device

A device that does not follow Ohm’s law

Kirchhoff’s loop rule

The sum of voltages around a closed loop equals zero

Series circuits

Components share the same current and voltages add

Parallel circuits

Components share the same voltage and currents add

Magnetic field

Region where magnetic forces act

Hall effect

Voltage generated across a conductor in a magnetic field

Wire in magnetic field

A current-carrying wire experiences a force perpendicular to both current and field

Magnetic dipole

A current loop that behaves like a magnet

Magnetic dipole moment

A measure of the strength and direction of a magnetic dipole

Magnetic fields created by

Moving charges or electric currents

Biot-Savart law

Describes the magnetic field produced by a current

Faraday’s law

A changing magnetic flux induces an electromotive force

Solenoid

A coil that produces a nearly uniform magnetic field used in electromagnets

Induction

The process of generating voltage from a changing magnetic field

Magnetic flux changes

Occurs when field strength area or orientation changes

Conductor

A material that allows charge to flow easily

Charge quantization

Charge exists in discrete multiples of the elementary charge

Field line rules

Electric field lines go from positive to negative and magnetic field lines form closed loops

Linear charge density

Charge per unit length

Electric dipole moment

A measure of separation of positive and negative charges

Electric potential

Energy per unit charge at a point

Electric potential energy

Energy due to position in an electric field

Dielectric material

An insulating material that increases a capacitor’s ability to store charge

EMF device

A source of voltage such as a battery or generator

Lenz’s law

Induced current opposes the change in magnetic flux that caused it

Self-induction

An inductor resisting changes in its own current

RL circuit behavior

Current changes gradually over time when switching on or off

Charge amplitude

Maximum charge in an AC circuit

AC current

Current that alternates direction

DC current

Current that flows in one direction

Electric potential vs electric field

Potential is scalar and easier to calculate while electric field is vector

Dielectric breakdown

Occurs when too much voltage causes an insulator to become conductive

Phase constant

Indicates the phase difference between voltage and current

Capacitor frequency behavior

Higher frequency decreases opposition to current

Inductor frequency behavior

Higher frequency increases opposition to current

Power transmission

High voltage and low current reduce energy loss in power lines