## This is a Free Service provided by Why Fund Inc. (a 501 C3 NonProfit) We thank you for your donation!

(1. Click on the course Study Set you wish to learn.) (2. If you wish you can click on "Print" and print the test page.) (3. When you want to take a test...click on anyone of the tests for that Study Set.) (4. Click on "Check Answers" and it will score your test and correct your answers.) (5. You can take all the tests as many times as you choose until you get an "A"!) (6. Automated college courses created from lecture notes, class exams, text books, reading materials from many colleges and universities.)

New

## Long-Term Learning

Learn efficiently and remember over time.

## Start Long-Term Learning

Get personalized study reminders at intervals optimized for better retention.
Track your progress on this set by creating a folder
Or add to an existing folder

## Add this set to a folder

• ### right-handed three finger rule

the rule that says if the thumb points in the direction of the charge's motion, the index finger points in the direction of magnetic induction and the bent middle finger points in the direction of magnetic force

### electromagnetic induction

term for the generation of current by means of a conductor's motion through a magnetic field

### magnetic flux

term for the quanity of flux linking a conducting loop

### the magnetic flux is changing.

When a single conducting loop or segment thereof is passing through a magnetic field, current is generated in the loop if and only if...

### ammeter

term for a meter used to measure small amounts of current

### False

True or False: The mere presence of a magnetic field is enough to induce current within a coil.

### magnetic field

Current is induced within a coil by relative motion between the coil and a(n) _____ ___.

### speed

The ___ of relative motion between a coil and a magnetic field determines how much current is prodced.

### strength

The current induced by a magnetic field depends on the ____ of the field.

### number of turns

Current varies directly with the ___ __ ___ in a coil.

### law of induction

law that says that a change in magnetic flux specifically induces potential difference, which instantaneously produces a current

the scientist who is famous for discovering electromagnetic induction

### opposes

Induced current is directed so as to create a magnetic field that ____ the motion causing the current.

### Lenz's law

the law that states that the current induced by a change in magnetic flux is directed so as to create a magnetic field that opposes the change

### opposing

According to Lenz's law, when the flux passing upward through the second coil increases, the induced current must create a(n) ____ magnetic field.

### similar

When the flux passing through the second coil decreases, the second coil's induced current must create a(n) ____ magnetic field.

### electric generator

term for a device that produces current by electromagnetic induction

### armature

term for the conducting loop that rotates between the poles of a pemanent magnet in a simple electric generator

### slip rings

term for the rings which rotate with the armature to allow constant contact betwee the armature and the brushes

### brushes

term for stationary pieces of metal that provide a path for the current to flow to and from the appliance powered by an electric generator

### alternating current (AC)

term for current that changes direction

### direct current (DC)

term for current that always flows in the same direction

### commutator

term for a split ring on which the ends of the loop terminate in a single-loop generator

### rotor

term for a magnet that rotates inside the stator

### stator

term for a stationary armature in a DC generator

### prime mover

term for the source of mechanical energy that drives a generator

### three-phase current

term for current composed of three currents phased 120 degrees apart

### torque

Since each force is exerted at a distance from the axis of rotation, each produces a(n) ___.

### torque arm

term for the perpendicular distance (r) from the axis of rotation to the line of the force

### motor

term for a freely rotating loop mounted in a magnetic field and fed with current that reverses periodically

### two-pole motor

term for a motor with a predominant north pole coupled with a single south pole

### hysteresis

term for the delay before a material conforms to an external magnetic field

### eddy currents

term for tiny currents that produce small magnetic fields working against the rotating armature in a motor

### electrochemical cell

term for a device that produces electrical current through a chemical reaction

### electrodes

term for two strips that are immersed in an aqueous solution

### aqueous solution

term for an ionic solid dissolved in water

### electrolyte

term for an aqueous solution in which electrodes are submerged

### salt bridge

term for a porous material soaked with a suspended aqueous solution

term for an appliance that uses a current's energy to do some type of work

### anode

term for a negative electrode, which supplies electrons to the conducting wire

### cathode

term for the positive electrode, which draws electrons from the conducting wire

### battery

term for a combination of two or more electrochemical cells

### series

If the cells in a battery are connected so that the anode of one cell is connected to the cathode of the next and so on down the line, the cells are connected in ___.

### current-generating capacity, smallest

The current delivered by cells connected in series is limited by the ______ _____ of the ____ cell.

### their individual voltages

The voltage of cells connected in series is the sum of ___ ____ ____.

### parallel

In a ____ combination of cells, all the anodes are connected and all the cathodes are connected.

### any individual cell's voltage

The voltage of parallel cells is the same as ___ ____ ___ ____.

### thermocouple

term for a complete circuit in which two conductors made of different materials come together at junctions maintained at different temperatures

### Seebeck voltage

term for a potential difference between junctions

### Seebeck effect

term for the appearance of the Seebeck voltage in an appropriate coupling of two conductors

### thermoelectric, temperature

The magnitude of the Seebeck voltage depends on...
1. The extent to which the two materials differ in their _____ characteristics and
2. The ____ difference between the junctions.

### thermoelectric generator

term for any device consisting of a thermocouple lodged within an apparatus that provides for the heating of one junction and the cooling of the other

### Peltier effect

term for the heating or cooling of a junction between two dissimilar conductors in the pathway of current

Example: