Test 3- MAGNETISM, Electromagetism & ELECTROSTATICS Flashcards
A single atom of barium has an atomic number (Z) of 56.
Indicating ___ positive charged within the nucleus, which cannot be broken down by ordinary means. (Chemical or Mechanical)
56
Each shell (or orbit) can be broken down into it’s various ___
Sub-Orbitals
Principal Quantum Number Rules (Slide 5)
and
Electron Configuration (Slide 7)
A ___ is a volume of space with a specific shape (S, P, D, F)
Review picture on slide #6 for a visual
Suborbital
The two electrons that inhabit it may be located anywhere within this volume
What are the four main types of sub orbitals?
Describe them (in shape)
Review picture on slide #6 for a visual
“S” (spherical)
“P” (dumbbell-shaped)
“D” (complex, cloverleaf-like)
“F” (even more complex shapes)
Sub orbitals refer to:
The different types of orbitals within an electron shell of an atom
Electron Configuration Slide #7
In 1819, who discovered that nearby electrical current will deflect a magnet, such as a needle of a compass?
Danish physicist Hans Oersted
Hans Orrsted established that all moving electric charges develop ___ around them.
Magnet Fields
When a charged particle is in motion, a ___ force field ___ to the motion will be created
- Magnetic
- Perpendicular
Define Electromagnetism:
The physical interaction among electric charges, magnetic moments, and electromagnetic fields
The intensity of magnetic fields is represented by what kind of lines?
Imaginary Lines
(Magnetism)
What is the perpendicular magnetic force called?
Orbital Magnetic Moment
Magnetic effect is established by:
Electrons spinning on their axis: called spin magnetic moment
(disruption of this axial spinning and the energy released as it reorients itself are physical basis that permit MRI)
Spin:
An exotic type of motion that electrons, protons, and neutrons all share.
Since the charged particles are moving, they develop a magnetic field surrounding themselves.
The K shell of every atom can hold a maximum of:
2 electrons
Since protons and electrons also have electric charge, they develop magnetic ___ and ___ poles
North and South
Primarily ____ create a significant magnetic field within an atom; as they are the charged particles in constant motion around the nucleus, which is the key factor in generating a magnetic field; while protons and neutrons also have a small magnetic field due to their intrinsic spin, their contribution is usually much smaller compared to electron
Electrons
What particle within an atom does NOT develop a magnetic field?
Neutrons
Which way to electrons rotate?
Either clockwise or counterclockwise
An electron spin creates the ___ field which is neutralized in electron pairs.
Magnetic
Atoms having __ numbers of electrons in any she’ll exhibit a very small magnetic field.
Odd
_____ is a quantum property of electrons that describes how they behave as if they are spinning around their axes
Electron Spin
Magnetic moment is caused by:
the motion of electrons in atoms
Spin: The spinning of an ____ around its own axis creates a magnetic moment
Electron
Spin: The spinning of an ____ around its own axis creates a magnetic moment
Electron
Orbital: The motion of an ___ around the nucleus creates a magnetic moment
Electron
When an electron and a proton are moving in a magnetic field, their magnetic field orientations are ___ due to their opposite charges; if a proton’s magnetic field curves clockwise, an electron’s will curve ___ in the same field, essentially meaning the magnetic field lines around them would be oriented in the opposite direction
- Opposite
- Counterclockwise
Protons and electrons are __ of each other
Opposite
Magnetic Moment:
Slide 14
Within a suborbital filled with its pair of electrons, the two magnetic moments must be ___, one up and one day, cancelling each other out to there is no net magnetic field for the suborbital
Opposite
What is magnetic dipole?
an entire atom with a magnetic field
- an atom that acts like a tiny magnet due to the magnetic field generated by the movement of its electrons, essentially behaving as a small current loop with a north and south pole, making the entire atom considered a magnetic dipole; this magnetic field arises primarily from the orbital and spin angular momentum of the electrons within the atom
When an atom has an odd number of electrons, What happens?
- At least one suborbital will not have its magnetic moments cancelled
because there will always be one unpaired electron, meaning its magnetic moment will not be counteracted by another electron with an opposite spin, making the atom paramagnetic
Electron pairing:
Electrons tend to pair up in orbitals with opposite spins, which cancels out their magnetic moments
Due to the movement of electrons around the nucleus, an atom develops a weak magnetic field, often referred to as its ____
- magnetic dipole
because the electron’s orbital motion acts like a tiny current loop, creating a north and south pole within the atom
Generally, the magnetic field produced by a single atom is very ___
Weak
Paramagnetism:
When materials have atoms with unpaired electrons (meaning their magnetic dipoles are not cancelled out), they exhibit paramagnetic behavior, meaning they are weakly attracted to an external magnetic field
Within an iron bar that has not been magnetized, magnetic dipoles within small regions tend to line up with each other, such that atoms north poles all point ____
What is this called?
- The same way
- Magnetic Domains
A ____ is a microscopic region within a magnetic material where the magnetic moments of the atoms are all aligned in the same direction
“magnetic domain”
Is iron easy magnetized?
Yes!
When an iron bar is magnetized, all of the regional magnetic domains line up uniformly with the external magnetic field (B)
Is this statement true or false?
True
This basically causes the iron bar to become magnetic itself
Materials that are easily magnetized are called:
Ferromagnetic Materials
Explain Magnetic Dipoles and Magnetic Domains:
- Most of atoms with most of the magnetic force in a single direction form a magnetic dipole
- A magnetic domain, describes a region within a magnetic material which has uniform magnetization.
This means that the individual magnetic moments of the atom are aligned with one another and point in the same direction.
Magnetic Dipoles:
A “magnetic dipole” refers to a tiny region within a material where the magnetic moments of atoms are aligned in the same direction, essentially acting like a tiny magnet
Magnetic Domain:
A “magnetic domain” is a larger region within a ferromagnetic material where many magnetic dipoles are aligned together, creating a larger, noticeable magnetic field; essentially, a domain is a collection of aligned dipoles within a material
Do all dipoles have the same size?
No! Dipoles vary in size and grow or shrink depending on the environment
When the magnetic dipoles or domains are not in a predominant direction, the object is magnetized.
True or False?
FALSE
The object is NOT magnetized
Do dipoles change when brought near the influence of an external magnetic field?
Yes!
What are the three types of magnets?
Ferromagnetic means:
Give examples
A material that exhibits strong magnetic properties, meaning it can be easily magnetized and retains its magnetism even after an external magnetic field is removed, allowing it to act as a permanent magnet
ex: Iron, nickel, cobalt
What are Natural magnets?
Lodestones ferromagnetic rock that behave as weak natural magnets
Permanent or Artificial Magnets:
Conventional magnets made from ferromagnetic metals in various shapes including bars, horseshoes, and discs
To magnetize a ferromagnetic object, what must happen?
A strong permanent magnet may be repeatedly stroked alongside it
A temporary magnet produced by moving electric current through a wire is called an ____
electromagnet
Electromagnets:
Temporary magnet produced by moving electric current, wire (solenoid) wrapped around an iron core then attached to an electric current running through the wire thus magnet field is created
What does Permeability mean?
The ease with which a material can be penetrated by a magnetic field, or how susceptible it is to being magnetized
What does retentivity mean?
The ability of a material to hold onto its magnetic field, or how long it is able to stay magnetic
Tapping on or jolting a permanent magnet outside of an external magnetic field shakes the magnetic domains back into random configurations, causing what?
The object to lose its magnetic field
What are conventional magnets made from?
Mixture of iron, nickel, cobalt, and other ferromagnetic materials
The ideal material has both ____ and ____
(Think convenient magnets)
High permeability and high retentivity
What does Non-Magnetic mean?
Give examples
Completely unaffected by magnets
Ex. Wood, Rubber
What does paramagnetic mean?
Give examples
Do paramagnetic mean they have dipole atoms and form domains?
- Slightly attracted to strong magnets
Ex. Oxygen, Sodium - Have dipole atoms but do not form domains
What material is somewhere between ferromagnetic and non magnetic?
Paramagnetic!
What type of material is completely unaffected by magnets?
Non-Magnetic
What material is very slightly attracted to a magnetic field shakes, and loosely influenced by an external magnet?
Paramagnetic
What does ferromagnetic mean?
Give examples
Strongly attached to magnets
Ex. Iron, Nickel
Ferro- = ___ or ___
“Iron” or “fire”
What does diamagnetic mean?
Give examples
Repelled away from magnets
Ex. Glass and water
____ are always dipolar or bipolar
Magnets
No matter how many times a magnet is broken in half, the remaining segments each retain their own north and South Pole.
Is this statement true or false?
True!
Magnetic monopole was found by Einstein
True or False?
Explain your answer
FALSE
Unlike electric charges, which can be separated completely into negative and positive object, NO magnetic monopole has ever been found
What magnet can be man made by using electricity?
Electromagnets
All electric currents produce a _____
Magnetic Field
The lines of a magnetic field are always ____
Closed loops, no beginning or ending
A small magnet created by the electron orbit is called a ____
Magnetic Dipole
An accumulation of many atomic magnets with their dipoles aligned creates a ____
Magnetic Domain
If all magnetic domains in an object are aligned, what happens?
It acts like a magnet
What does a magnetic field describe?
Describes the magnetic force exerted on a magnet
Lines of force are MOST concentrated where?
At the poles
Magnetic lines of force flow ____ from the North Pole, and __ from the South Pole
- Outward
- Inward
Magnetic lines of force will always run ___ to an associated electrical field
(for all electromagnetic fields)
Perpendicular!!!
Between two bar magnets, the magnetic lines of force are strengthened (more concentrated) by ____ material
ferromagnetic
The lines of force are weakened (deviated) by ___ materials placed between magnets.
Look at slide 36 for a visual.
Diamagnetic Materials
What are the Two Laws of Magnetism?
1) Like poles repel each other
2) Unlike poles attract
Meaning a north pole of a magnet will be attracted to a south pole, but repelled by another north pole.
Gauss Law
Slide 38
What is the Law of Magnetic attraction and repulsion states:
Unlike magnetic poles attract each other, while like magnetic poles repel each other
Line of force in the same direction will ___ each other
Repel
Line of force in opposite direction will ____ each other
Attract
Magnetic induction is:
the process by which a material temporarily acquires magnetic properties when placed near a magnet
Abbreviation for Gauss:
G
Gauss (G) is used for ___ magnets
Give an example
Small
Ex. Cabinet door magnets which have about 1000 G
Earths magnetic field is about 1 G at the poles and 1/2 G at the equator
Tesla (A) is used for ___ magnets
Give an example
Very large
Ex. Typical MRI machine generates 1.0-1.5 T
T T=1 t _____ G
10,000
Electrostatics is the study of:
Stationary electric charges
An object is said to be ___ if it has too few or too many electrons.
This can be created by what three things?
- Electrified
- Can be created by contact, friction, or induction
Electrodynamics is the study of:
Electric Charges in motion
What is a conductor and an insulator?
A conductor is any substance through which electrons easily flow.
An insulator is any material that does not allow electron flow.
The small magnet created by the electron orbit is called a____
Magnetic Dipole
An accumulation of many atomic magnets with their dipoles aligned creates what?
A magnetic domain
If all magnetic domains in an object are aligned, it acts like a magnet
What are the three principal types of magnets?
- Naturally (Earth)
- Artificially induced permanent magnets
- Electromagnets (wire wrapped around an iron core)
An electric current produces a ____
Magnetic Field
What did Oersted experiment discover?
- Moving electrons create a magnet field
- The magnetic field created by the current circles the wire
- The strength of the magnet field is related to the speed of the moving electrons
Oersted Experiment:
Oersted discovered that a compass needle below a wire
(A) pointed north when there was ___ a current
(B) moved at right angles when a current flowed one way
(C) moved at right angles in the opposite direction when the current was reversed
- Not
Electromagnetism is a branch of physics that studies the interaction between____ and ___ fields and electrically charged particles.
It’s responsible for many phenomena, including the creation of magnetic fields and electric currents.
Danish scientist Hans Christian Oersted accidentally discovered electromagnetism in 1820 when he found that electric currents produce magnetic fields.
- Electric
- Magnetic
True or False
The strength of the magnetic field increases with an increase in the current
True
When electric current flows through a wire, it generates a magnetic field around it. The intensity of this magnetic field is directly proportional to the magnitude of the current
As the current increases, the magnetic field around the wire becomes ____
Stronger
Are electric and magnetic field closely intertwined?
Yes and understand many circumstances is is impossible to consider the two separately
____ is a process in which a conductor is put in a particular position and magnetic field keeps varying or magnetic field is stationary and a conductor is moving
Electromagnetic Induction
Electromagnets:
By inserting an iron bar into an electrified solenoid, the magnetic field is _____
If the director of the electric current is reversed, the north and south poles of the field ___ position
- Greatly strengthened
- Reverse
A solenoid’s function is to:
convert electrical energy into mechanical energy
The strength of an electromagnet is determined by what three things?
Slide 56.
- the amount of current flowing through the coil
- the number of turns in the coil
- the material the core is made from
What is an example of a solenoid in the x ray room?
Dentent Locks
Both a solenoid and electromagnet demonstrate magnetic properties ONLY while electric current is stopped or flowing?
Flowing!
First Law of Electromagnets also known as Faradays Law
Magnitude of induced current depends on the what 4 factors?
1) Magnetic field strength: A stronger magnetic field will induce a larger current
2) The speed of the motion between lines of force and the conductor
3) The angle between the magnetic lines of force and the conductor
4) The number of turns in the conducting coil
The intensity of the magnetic field at the wire must be ____ to induce a current.
If the magnetic field intensity is ___, there will be no induced current.
- Changing
- Constant
The relationship between current and changing magnetic field is called ______
Electromagnetic Induction
Coil of wire is connected to a current-measuring device called an __
Ammeter
_____ is a branch of physics that studies the behavior of stationary or slow-moving electric charges
Electrostatics
True or False
An object can become electrified any time it developed either an excess of electrons or a deficiency of electrons.
True
Electricity is the result of ___ movement (charges in motion)
Electron
Electrification is the process of:
Electrons charges being added or subtracted from an object
Everything in nature is __ __
Electrically Neutral
(equal amount of positive and negative charges)
Can negative and positive charges be separated to produce a charged object?
Yes.
this process is called “charge separation” and is the basis for static electricity, where rubbing two materials together can transfer electrons, leaving one object with a net positive charge and the other with a net negative charge
Can an uncharged object become charged?
Yes! An uncharged object can be charged by either gaining or losing electrons
The ___ acts as an essentially infinites reservoir for charge- by __ structures, abt static electricity built up on them can be dissipated.
Ground
Grounding
What is the unit of electric charge?
Coulomb
The rate of flow of electric charge is called ___ and is measured in amperes (A) which is what?
- Electric Current
- amperes is the flow
Electric Current (electricity) is defined as:
the amount of electric charge flowing per second
One coulomb of negative charge represents:
6.3 x 10^18 electrons
An electrical charge can be l either positive or negative. A positive charge or 1 Coulomb would mean the object was deficient of ____ electrons.
This will still result in a spark, but electron flow will be from the other object to the positively-charged object.
6.3 x 10^18 electrons
Coulombs Law
Force between two charged objects is ____ proportional to the product of their charges and inversely proportional to the square of the distance between them.
Directly
The greater the charges on the objects, the ___ the force between them
The greater the distance between object, the ___ the force between them
- Larger
- Lesser
What are The Five Laws of Electrostatics?
1) like charges repel each other, opposite attract
2) in solid object, only negative charges (electrons) can move because they are outside the nucleus
3) in solid objects, charge will concentrate at the greatest curvature of the surface
5) The force of electric charge follows Coulombs Law
Understanding The Laws of Electrostatics:
Slides 71-73
What three ways can objects become electrified?
- Friction
- Contact (Conduction) have to touch
- By induction
Electromotive Force (EMF) is:
Electro= ____
Motive= ____
the amount of energy a source transfers to each unit of electric charge, measured in volts
- Electron
-Motion
In order to distance themselves from each other, electrons will always spread out evenly across the surface of two objects in contact.
This results in ____ of charge at the ___ possible value on the two objects if they are then separated.
- Equalization
- Lowest
True or False
Even if one object is neutral or uncharged, there is still a relative difference in potential or charge between it and a charged object, so electrification will occur
True
Electrification by induction does what:
Induced a charge in another nearby object without touching it
- An neutral object will become electrically polarized when a charged object is brought near and attracts opposite charges towards it
Using an electroscope to detect radiation
Slides 87-88
Since the Earth is essentially an infinite reservoir of electrons, any charged body can be ___ if it is grounded
Neutralized
Grounding a positively charged body causes electrons to move up from the ground to ___ the body.
Neutralize
Grounding a negatively charged body drives its excess electrons to ground, again ___ the body
Neutralizing
Read Summary Slide 91-94!
The maximum number of electrons that can occupy a shell under any condition is equal to:
2N^2
Where N is the shell number
The outermost shell of the atom can never hold more than ___ electrons.
8!
In solid object, only negative charges (electrons) can move. True or False?
True
The force of electric charge follows, what law?
Coulombs Law
Magnetic Lines of force will always run ____ to an associated electrical field.
Perpendicular
Factors that govern solenoids and electromagnetism:
- Diameter of coil (wire)
- Length of coil
- Both a solenoid and an electromagnet demonstrate magnetic properties only while electric current is flowing
In solid objects, electrical charges exist only on the surface of the object.
True or False?
True
In solid objects, charge will concentrate at the ____ of the surface.
Greatest Curvature
