Ch 5

Question 1

Electricity vs gravity

Answer 1

Gravity

Can never be repulsive- always pulls objects together

Electricity

Can attract and repel based on charge

electricity is 30 times greater

Question 2

Describe lightening

Answer 2

Rain/ wind cause uneven distribution of electrons in cloud= build up of negative at bottom= positive build up on earth’s surface (net positive charge)= build up creates a voltage between cloud and ground. Lightening strike is the electrical current that runs between the two when the voltage is high enough

Question 3

Coulomb’s law

_ charges repel one another, and _ charges attract one another

The force between any two _ objects is proportional to the product of their _divided by the square of the _

Answer 3

Coulomb’s law

like charges repel one another, and unlike charges attract one another

The force between any two electrically charged objects is proportional to the product of their charges divided by the square of the distance between them

Question 5

Electrical field

Every _ exerts forces (proportional to _)) on its surroundings to create an electric field

Answer 5

Electrical field

Every charged object exerts forces (proportional to 1/(d^2)) on its surroundings to create an electric field

Question 6

William Gilbert

First _

Discovered magnetic poles= two ends north and south=_

Cut one in half= two smaller _

Learned

Magnetize iron and steel by rubbing with _

Hammering iron makes it _

Irons magnetism can be destroyed through _

Answer 6

William Gilbert

First magnet studies

Discovered magnetic poles= two ends north and south= dipole magnet

Cut one in half= two smaller magnetic dipoles

Learned

Magnetize iron and steel by rubbing with lodestone

Hammering iron makes it magnetic

Irons magnetism can be destroyed through heating

Like magnetic poles repel and opposite poles attract (forces)

Question 7

describe aurora

Answer 7

Charged particles interacting with earths magnetic field

At poles

The convergence of magnetic field of force lines enhances the effect of visible light displays from incoming solar particles interacting with the magnetic field.

Question 8

Connection between _ and _ required the invention of the battery and the electrical circuit

Answer 8

Connection between electricity and magnetism required the invention of the battery and the electrical circuit

Question 9

Luigi and life’s electrical force

Electricity caused frogs legs to contract= _

which separates _ from _ matter

And poking with 1 iron and copper fork

Answer 9

Luigi and life’s electrical force

Electricity caused frogs legs to contract= animal electricity

which separates living from inanimate matter

And poking with 1 iron and copper fork

Question 10

Electrical current=

Answer 10

Flow of charged particles- negatively charged electrons

Question 11

Volta vs Luigi

explain

how both right?

Answer 11

Galvani’s effects were caused by chemical reactions between the metals and the salty fluids of the frogs’ legs.

Electrical charges can be induced to flow by chemical reactions

In retrospect, both of these scientists had part of the truth. Muscle contractions are indeed initiated by electrical signals and electrical charges can be induced to flow by chemical reactions​

Question 12

Volta invented _

Converts stored _ into _ of electrons

Answer 12

Volta invented battery

Converts stored chemical energy into kinetic energy of electrons

Question 13

Life force present day implications

Use of magnets/ electricity to heal

Magnets can cause the_ to increase the _, which allows cells to pick up more _ and release more _

Answer 13

Magnets can cause the separation of blood cells to increase the available surface area, which allows cells to pick up more oxygen and release more energy

Question 14

Electric circuits

_ path of material (electrical conductors) that carries _

Three parts of a circuit

• Source of energy
• Closed path through which energy can flow
• Device to use the electrical energy

Answer 14

Electric circuits

Unbroken path of material (electrical conductors) that carries electricity

Three parts of a circuit

• Source of energy
• Closed path through which energy can flow
• Device to use the electrical energy

Question 15

OHMS law

The current in circuits is directly proportional to the _ and inversely proportional to the _. The higher the electrical “_,” the higher the flow of charge. The higher the _ to flow, the smaller the flow

Volts= current (_) x resistance (_)

Answer 15

The current in circuits is directly proportional to the voltage and inversely proportional to the resistance. The higher the electrical “pressure,” the higher the flow of charge. The higher the resistance to flow, the smaller the flow

Volts= current (amps) x resistance (ohms)

Question 16

Current= amount of _ flowing past a point in the wire per _

1 _ of current= 1 coulomb of charge per second

Voltage= _ produced by the energy source in the circuit

Measured in _

Electrical resistance= how hard to _ electricity through wire

measured in _

The higher the resistance= more electron KE converted to _

Answer 16

Current= amount of electrons flowing past a point in the wire per second

1 amp of current= 1 coulomb of charge per second

Voltage= pressure produced by the energy source in the circuit

Measured in volts

Electrical resistance= how hard to push electricity through wire

Measured in Ohms

The higher the resistance= more electron KE converted to thermal E

Question 17

Temperature effect

Answer 17

High temp= the atoms that make up the conductor start to vibrate more vigorously. As a result, mobile electrons in the conductor may collide more often with vibration atoms= increased electrical resistance*

Easier to walk through a crowd standing still vs people moving

Question 18

Electric power

The power consumed by an electrical appliance is equal to the product of the _ and the _

EQT?

Answer 18

Electric power

The power consumed by an electrical appliance is equal to the product of the current and the voltage

P (watts)= current (amps) * voltage (volts)

P=I*V

Question 19

Nerve impulse

Dendrites receive _

Axon conducts _

Myelin sheath _ axon from neighboring electrical _

Answer 19

Nerve impulse

Dendrites receive incoming signals

Axon conducts outgoing signals away from the nerve

Myelin sheath insulates axon from neighboring electrical interference

Question 20

Oerstad exp

whenever _ flows through a wire, a _ will appear around that wire. A compass brought near the wire will twist around until it points along the direction of that _.

Answer 20

whenever electrical charge flows through a wire, a magnetic field will appear around that wire. A compass brought near the wire will twist around until it points along the direction of that magnetic field.

Question 21

Electromagnet

A device composed of a coil of wire that produces a _ when an electrical charge runs through the wire

Answer 21

Electromagnet

A device composed of a coil of wire that produces a magnetic field when an electrical charge runs through the wire

The stronger the current (more electrical charge pushed through wire), the stronger the magnetic field will be

Question 22

how does an electrical motor work

Answer 22

Electrical motor

2 permanent magnets

Rotating loop of wire between the magnets around electromagnet

Current switch on creates magnetic field and each pole is atrracted to the perm magnets.

Once aligned, the current flips to reverse the magnetic poles

The repulsive forces between like magnetic poles act to continue the rotation.

By alternating the current in the loop, a continuous rotational force is kept on the wire, and thus the wire keeps turning.

As the electromagnetic coil spins, the current flow direction is switched back and forth causing continued rotation of the coil as it responds to attraction and repulsion of N and S poles.***

Question 23

Why no monopoles

Answer 23

If you break a magnet down to one last individual atom, you still have a dipole field because of the atomic-scale current loop. If you try to break the atom down further, the dipole field will disappear and there will be no magnetism except that associated with the particles themselves. Thus, magnetism in nature is ultimately related to the arrangement of electrical charges rather than to anything intrinsic to matter itself.

Question 24

Neodymium magnet solutions (3)

Answer 24

Recycling

New technology that doesn’t need the magnet

New mineral

Question 25

describe MRI

Answer 25

Motion of electrons in atoms create a current that produces a magnetic field and so does the rotation of the nucleus of the atom

Nucleus= small dipole magnet

MRI produces magnetic field that enter tissue and causes nucleus to rotate at a characteristic frequency

This effect causes the nuclei to absorb radio waves whose frequency is times to coincide with the rotation

By monitoring which radio wave frequencies are absorbed, you know tissue type (x-ray can’t)

Question 26

Faraday EXP

Electrical fields and electrical currents can be produced by changing _.

EXPLAIN STORY (2)

Answer 26

2 coils of wire side by side with one battery connected to 1

Even though the second coil of wire was not connected to a battery, a strong electrical current developed in it.

the loop of wire through which current was running produced a magnetic field in the neighborhood of the second loop. This changing magnetic field, in turn, produced a current in the second loop by means of a process called electromagnetic induction

Moving a magnet into the region of a coil of wire causes a current to flow in the circuit, even in the absence of a battery or other source of power.

Question 28

Electrical generator

Answer 28

Place a loop of electrical wire with no batteries or other power source between the north and south poles of a strong magnet.

From the point of view of the electrons in the wire, any rotation changes the orientation of the magnetic field. The electrons sense a changing magnetic field and hence, by Faraday’s findings, a current flows in the loop. If we spin the loop continuously, then a continuous current flows in it

Question 29

Electric generator vs electric engine

Answer 29

Generator

Some energy turns the shaft that spins coils of wire in a magnetic field: Kinetic energy into electrical energy

Engine

Electric energy is turned into kinetic energy of spinning shaft

Question 30

AC vs DC

Answer 30

AC eventually won because it is easier to transmit alternating current over long distances

Question 31

Maxwell’s equations

_ force

A term used to refer to the unified nature of electricity and magnetism

Equations

• Coulomb’s law: like charges _, unlike _
• There are no magnetic _ in nature
• Magnetic phenomena can be produced by _
• Electrical phenomena can be produced by _

Answer 31

Maxwell’s equations

Electromagnetic force

A term used to refer to the unified nature of _ and _

Equations

• Coulomb’s law: like charges repel, unlike attract
• There are no magnetic monopoles in nature
• Magnetic phenomena can be produced by electrical effects
• Electrical phenomena can be produced by magnetic effects