Last Ditch Attempt At Physics

Front 1

closed circuit:

Back 1

A circuit in which the source of emf is connected to the circuit so that current begins to flow.

Front 2

emf: (E)

Back 2

The work done per unit charge by a source that forces electrons to move in a direction opposite to the electrostatic field inside the source.

Front 3

The junction rule:

Back 3

the sum of the currents entering any junction must equal the sum of the currents leaving that junction.

Front 4

The loop rule:

Back 4

the sum of the potential differences across all the elements around any closed-circuit loop must be zero.

Front 5

load resistance:

Back 5

The external electrical resistance that the terminal voltage of a battery is hooked up to.

Front 6

time constant: (Symbol = tRC)

Back 6

The time required for a capacitor C in an RC circuit to charge from zero to 63.2% of its maximum value, or to discharge to 36.8% of its fully charged value.

Front 7

Ampère's Law:

Back 7

The law stating that the sum of the product of the magnetic field produced by a current I times a path segment Δl forming a closed path around the source of current equals the permeability of free space m0 times I.



is the component of the magnetic field that lies parallel to Δl.

Front 8

cathode ray tube: (CRT)

Back 8

A display device consisting of an electron gun made up of a heater, a cathode, and a positively charged anode. The cathode is heated to a sufficiently high enough temperature that the electrons in the cathode material have sufficient kinetic energy to escape the cathode. The free electrons are subsequently attracted to the anode and ultimately strike a specially prepared screen that fluoresces when it is struck by the electrons.

Front 9

dip angle:

Back 9

The angle between the Earth's magnetic field and surface of the Earth.

Front 10

electric motor:

Back 10

A generator that runs in reverse taking electricity and producing mechanical torque

Front 11

electromagnet:

Back 11

A multiturn coil of wire that when energized with electric current produces a magnetic field around it. Sometimes referred to as a solenoid.

Front 12

ferromagnetic:

Back 12

Strongly magnetic materials such as iron, cobalt, and nickel whose electron spins do not cancel completely.

Front 13

gauss:

Back 13

The cgs unit for magnetic field. It is related to the SI unit of magnetic field, the tesla (T), by: 1 T = 10^4G

Front 14

magnetic declination:

Back 14

The difference in angle between magnetic north and geographic north. The magnetic declination differs from point to point on the Earth.

Front 15

magnetic domain:

Back 15

Large groups of atoms whose spins are aligned. The size of a magnetic domain is typically 10-4 cm to 0.1 cm.

Front 16

magnetic field:

Back 16

The field associated with the force surrounding magnetic materials. The direction of the magnetic field is in the direction that the north pole of a compass would point with the compass at that location.

Front 17

permeability of free space: (Symbol = m0)

Back 17

A magnetic proportionality constant.

4πx10-7 Hm-1

Front 18

solenoid:

Back 18

A multiturn coil of wire that when energized with electric current produces a magnetic field inside its core and around it.

Front 19

Tesla (T)

Back 19

The SI unit of magnetic field. It is related to the cgs unit of magnetic field, the gauss (G), by:

1 T = 10^4G

Front 20

Permeability of free space constant

Back 20

What is this?

Front 21

back emf:

Back 21

An induced emf appearing in electric motors that tends to reduce the applied current in the motor.

Front 22

alternating current generator:

Back 22

A device that converts mechanical energy to electrical energy.

Front 23

direct electric current generator:

Back 23

A device that takes alternating current and converts it to one polarity to produce a steady DC current.

Front 24

Lenz's law:

Back 24

The polarity (direction) of the induced emf is such that it produces a current whose magnetic field opposes the change in magnetic flux through the loop. That is, the induced current tends to maintain the original flux through the circuit.

Front 25

motional emf:

Back 25

The emf induced in a conductor moving through a magnetic field.

Front 26

What is this equation?

Back 26

Faraday's law of induction

Front 27

The proportionality constant that relates self-induced emf to the time rate change of the current through the circuit producing the self-induced emf.

Back 27

Induction

Front 28

The product of the magnetic field perpendicular to a loop of area A.

Back 28

Magnetic flux