General Physics 2 Midterm Test

Composed of particles with different charges: neutrons, protons ,(+C) , and electrons (-C)

Electric charges are usually represented by q.

The SI unit of charge is the coulomb (C).

Represented by e. It is the electric charge carried by a single proton.

has a charge of + e

has a charge of – e.

unit of electric charge

Coulomb’s constant

Measure of the ease at which an electric charge moves through a material.

Materials that readily allow the flow of charges. Metals are good ___ since they have plenty of free electrons that can easily move in a material.

Materials that resist the flow of charges. Examples: rubber, plastic, mica, paper, glass, & air.

Intermediate between conductors & insulators. Examples: silicon, germanium and gallium arsenide. In pure form, ___ have low conductivity. Through the process of doping, atoms of various elements are added in small amounts to semiconductors to increase conductivity. ADDING to a conductor = increase conductivity

A material that has practically no resistance to the flow of charges. a substance, especially a metal, that allows an electrical current to move freely through it at a very low temperature. magnets

• Results when two different materials are rubbed together.

  • There is contact

• One material will have a positive charge, while the other negative.

  • Loses electrons (positive, stands), Gains electrons (negative)

• Requires physical contact between a charging (source) body & a neutral body.

• A neutral body will transfer electrons to a positive body.

  • Ex. positive body = outlet

• A negative body will transfer electrons to a neutral body.

• The process wherein a nearby neutral body is charged without physical contact by a charged body.

  • Ex. wireless charging

• The negative charges on the neutral body are attracted toward the charging body if the latter is positive.

  • They are repelled from the charging body if it is negatively charged.

• This effect is known as polarization.

• Earth is a reservoir of charges.

• Electrons from a neutral body will travel down the ground if the charging body is negative.

• Electrons will travel up the ground connection to the neutral body if the charging body is positive.

• Total charge of an isolated system remains constant.

• Charges cannot be created nor destroyed.

• In any charging process, charges are merely transferred from one body to another.

• The magnitude of electrical force between two charged particles is directly proportional to the product of the magnitude of their charges and inversely proportional to the square of the distance between them.

• three or more

• Each charge will exert a force on another charge as if no other charges are present.

• The total force that a particular charge experiences due to a collection of charges is the vector sum of all individual forces.

is a noncontact force

• The space surrounding a charged body

• cause any charged particle placed in it to experience an electric force.

• exists in the region of space around a charged object or a source charge

Lines of force start from ___ charged particles and end on _ charged particles.

The greater number of lines of force, the __ the field.

The strength of the electric field at a point due to the source charge

Physicists use a unit ___ charge as the test charge in defining an electric field. This test charge and the electric field are usually represented by qo and E respectively.

• the charge (electron) “pusher.”

• causes current to flow/move.

Unit for voltage

• Italian physicist

• known especially for the invention of the electrochemical cell, aka the battery in 1800.

• flow of charge (electrons) within a conductor or how fast charge is moving.

• Charge will only flow if there is a voltage source (potential difference).

Unit for Current

• French physicist and mathematician.

• One of the main discoverers of electromagnetism.

• SI unit of measurement of electric current, the ampere, is named after him.

• opposes the push from the voltage source.

• affects the speed of the current.

Unit for Resistance

• German physicist

• determined that there is a direct proportionality between the voltage applied across a conductor and the electric current.

Length and resistance are ___ proportional

CROSS-SECTIONAL AREA and resistance are ___ proportional

Temperature and resistance are ___ proportional

State the relationship between current, voltage, and resistance.

Formula of Ohm’s Law

voltage and current are __ proportional

Resistance and Current are __ proportional

Voltage and Resistance are __ proportional

The rate at which a device changes electric current to another form of energy

SI unit for power

formula for electric power

A passive two-terminal electrical component that implements electrical resistance as a circuit element.

In electronic circuits, ___ are used to reduce current flow and to divide voltages.

Is a device that stores energy and makes it available in an electrical form.

Converts chemical energy into electrical energy or vice versa

An electrical component that can break an electric circuit, interrupting the current or diverting it from one conductor to another.

the positive side is in which side of a battery

the negative side is in which side of a battery

malfunction

• Each device occurs one after the other sequentially.

• The Christmas light dilemma: If one light goes out all of them go out.

• Electrons only have one path to flow through

• exists where components are connected across the same voltage source.

• are similar to those used in homes.

• There are multiple paths for the current to flow through

• each + all

• any closed path going through circuit elements.

• intersection of wire between other wires

• any region on a circuit between two circuit elements

The sum of the potential drops (Resistors) equals the sum of the potential rises (Battery or cell) around a closed loop.

(Conservation of Energy)

Kirchhoff's Voltage Law (KVL)

• The sum of the magnitudes of the currents going into a junction equals the sum of the magnitudes of the currents leaving a junction.

• IN = OUT (current)

• (Conservation of Electric Charge)

• Kirchhoff's Current Law (KCL)

VOLTAGE: coming out of positive

VOLTAGE: coming out of negative

Current and Resistance: same direction

Current and Resistance: different direction

ability of magnetic material to attract/repel other magnetic materials.

materials that are able to attract other magnetic materials

• materials that are attracted to a magnet. (i.e. iron, nickel, cobalt and some alloys)

• can be made using magnetic materials.

• Anything that has magnetic properties can be a magnet

• such as wood, paper and glass, cannot be made into magnets.

• No magnet content

Portions of a magnet, usually near its end, where the magnetic force is greatest.

process of making a material temporarily or permanently become magnetic.

region of space where a magnet is capable of exerting a force on a magnetic material.

Electric fields surround a _

magnetic fields surround a _.

Electric fields: start from a … charge and end on a ….charge.

Outside a magnet, the lines are directed from the --- pole to the ---pole.

Inside a magnet, they run from the --- pole to -- pole.

determines the direction of magnetic fields and currents

use to determine: direction of current; direction of magnetic force ; and direction of magnetic field

Produced by a magnet represented by lines.

• Earth’s magnetic field is about 5x10-5 T

• Weber per square meter (Wb/m2) old name for ___.

• Magnitude of magnetic field.

• Attracts and repels when two lines of force are both close together.

• is on a moving charge:

  • if an electric charge q moves with a velocity v through a magnetic field B, a ___ is exerted on the charge.

Small numbers of dopant atoms can change the ability of a semiconductor to conduct electricity

atoms of various elements are added in small amounts to semiconductors to increase conductivity.

The material with the higher -- will attract more electrons.

SECOND RIGHT HAND RULE

thumb

SECOND RIGHT HAND RULE

index finger

SECOND RIGHT HAND RULE

middle

There are multiple paths for the current to flow through