physics week 2 quiz

Magnetic fields are always created around:

all moving electric charges develop magnetic fields around them

A small magnet or compass needle will always be deflected by nearby:

electrical current

Materials that are easy to magnetize and to demagnetize are said to have high:

permeability

When iron is fabricated into a magnet, the magnetic domains:

align

Magnetic retentivity is a material’s ability to:

retain or hold onto its magnetism over time

Diamagnetic and 2 examples

repel away from magnets; ex: glass and water

paramagnetic and 2 examples

slightly attracted to magnets; ex: oxygen and sodium

ferromagnetic and 2 examples

easily magnetized; ex: iron and nickel

non-magnetic and 2 examples

unaffected by magnets; ex: rubber and wood

Types of magnets and describe them

-lodestones (natural)

-artificial or permanent (magnetized by magnetic fields)

-electromagnetic (can be human-made by using only electricity)

The north pole of a compass needle points the Earth’s:

South geographic pole

When a charged particle moves in a straight line, a magnetic field is:

induces perpendicular to the particles motion

Charge is measured in the metric system in units of:

Coulomb

Only _____ are free to move in solids

electrons

Where are electric charges found in a conductor?

on the external surface

Two charged particles held close together are released. As the particles move, their velocity increases. The two particles must have:

opposite charges

When the electrical charges move through a solid object, what happens?

only the outer electron shells move

How can electrical charge be neutralized?

conducted to the ground

For a solid object, electric charge concentrates at:

The greatest curvature of the surface

When the distance between two charged objects is cut in half, the electrical force between them is:

quadruple

An object can become charges by:

friction, contact (conduction, and induction)

The electrical force generated between charges depends on:

how large the charge is and how far apart the charge is

Hans Christian Oersted discovered that all moving electric charges develop _____________ __________ around them.

magnetic fields

Oersted's discovery would eventually lead to the development of both ______ and ______.

motors, electrical generators

For a charged subatomic particle, the direction of spin determines the orientation of the magnetic field, called its ___________  ____________.

magnetic moment

Within an atom, each specific orbital can accommodate one electron with its magnetic moment pointing _____ and one electron with its magnetic moment pointing _______.

up, down

If an atom has an odd number of electrons, a small net magnetic field will be generated around the entire atom, called a _________ _________.

magnetic dipole

Materials which are easily magnetized are called _______________ materials.

ferromagnetic

Lodestones are ferromagnetic rocks that behave like weak ____________ magnets.

natural

The ease with which a material can be penetrated by an external magnetic field (and thus magnetized) is called its ____________.

permeability

The ability of the material to retain or hold onto its magnetism over time is called its _________________.

retentivity

Most______ or _______ magnets are made from mixtures or iron, nickel, and cobalt.

permanent, artificial

_____________ materials are only slightly attracted to strong magnets.

paramagnetic

_____________ substances are actually repelled away from magnets.

diamagnetic

Magnets always remain ______ or ______, retaining two poles (north and south).

dipolar, bipolar

By passing electricity through a coil of wire, (or solenoid), an ___________ is created with north and south poles.

electromagnet

The strength of an electromagnet can be further multiplied by inserting an _________ _________ within the coil of wire.

iron bar

A magnetic field follows distinct lines of force which take on the shape of _____________ ______________.

elephant ears

The magnetic lines of force flow _______ from the north pole, then circulate around and flow ______ the south pole.

outward, into

The magnetic field is strongest and most concentrated at the ________.

poles

Magnetic lines of force will always be ____________ to the lines of force of the associated electrical field.

perpendicular

Since opposite magnetic poles attract, the true north pole of a compass needle points toward the earth's ___________ magnetic pole is geographically north at this time in geological history.

south

___________ Law states that the strength or intensity of the magnetic field is proportional to the product of the pole strengths, and also follows the inverse square law.

Gauss

The two common units for magnetic strength are the ______ and the______ .

Tesla (T), Gauss (G)

One Tesla = _________ Gauss.

10,000

Electrostatics is the study of electrical charges at ___________>

rest

An object becomes ____________ any time it develops either an excess of electrons or a deficiency of electrons.

electrified

The ground of the earth acts as a kind of infinite ____________ for electrical charge.

reservoir

The unit for electrical charge is the ______ , which represents slightly more than 6 ______ electrons for a negative charge.

Coulomb, billion billion

A positive charge of 1 Coulomb would mean that the object was ___________ of 6.3 x 10¹⁸ electrons.

deficient

In solid objects, only ________ charges can move.

negative

In solid objects, electrical charges will concentrate at the greatest ____________of the surface.

curvature

Coulomb's law states that the amount of force generated by electrical repulsion or attraction is proportional to the _________ of the two charges, and also follows the inverse square law.

product

Three ways to minimize static discharges (sparks) are:

1. Place dielectric or insulator materials around electrical wires and devices.

2. Grounding metal structures by providing a conductive path (wire).

3. Keep the humidity high (above 40%).

Electrification by contact or conduction occurs whenever a ___________ ____________ exists between two objects that touch each other.

potential difference

When two charged objects touch, electrons will always flow toward those surfaces that are __________ ____________ positive.

relatively more

The force created by any electrical potential difference is referred to as _______, abbreviated ______.

electromotive force, EMF

When two charged objects that have been in contact are then separated, the charge remaining on both objects will always be equalized at the _____________ _____________ value.

lowest possible

For an exchange of electrons to take place it is not necessary that one object be negatively charged and the other positively charged - only that there is _____________ _____________ in potential or charge

any difference

Electrification by ______________ occurs when a charged object creates a charge in another object nearby without directly touching it.

induction

A metal bar which has been induced to have negative charge accumulate at one end (pole) and positive charge at the other end has been __________________.

grounded

In an electroscope, when a positive electrical charge is distributed across the surfaces of the leaves of metal foil, they will ______.

seperate

The charged foil leaves will move back together as this positive charge is neutralized by incoming electrons. Th electrons are supplied whenever radiation enters the electroscope, because radiation will __________ molecules in the air surrounding the foil leaves.

ionize

The simplest example of a radiation detection device using the electroscope is the personal __________ ____________.

pocket dosimeter

Regarding the movement of an electric charge from one atom to another:

Both positive and negative charges can move

Only positive charges can move

Usually inner-shell electrons move

Usually outer-shell electrons move

Usually outer-shell electrons move

Electrostatics:

concerns resting electric charges

governs the movement of electric charges in a conductor

is the conversion of kinetic energy

is the study of photon radiation

concerns resting electric charges

Coulomb’s law states that electrostatic force is:

inversely proportional to the square of the distance between charges

Which of the folling is a method of electrification?

excitation

Induction

Resonance

Transmission

Induction

The unit of electrostatic charge is:

coulomb

The principal electrostatic law states that:

An electron will repel an electron

A lodestone is an example of:

a natural magnet

If two magnets are brought together, north-to-north poles will _____, whereas north-to-south poles will ______.

repel,attract

A material which is slightly repelled by a magnet is classified as:

diamagnetic

Electrification occurs through the movement of:

only electrons

Two positive charges next to each other will do what according to the laws of electrostatics?

repel

The relationship between electromagnetic force and distance (Coulomb’s Law) resembles which law that is applied to electromagnetic radiation and distance?

Inverse Square Law

The term “paramagnetic“ refers to materials that have what?

weak magnetic fields

If you are holding a wire carrying a current in your right hand, and the current moves in the direction your thumb points, what is the direction of the magnetic field?

The same direction

The opposite direction

The direction your fingers point

The opposite direction your fingers point

The direction your fingers point

A type of electromagnet created by a current through a coil of wire is called a?

Solenoid

In a magnet, the magnetic field lines must always:

Reach from the north pole to the south pole

The SI unit for measuring magnetic field strength is:

tesla

Permeability is the ability of a material to:

be magnetized

One Coulomb of negative charge represents: _______ electrons

6.3 × 10¹⁸