Will physics quiz study magnetism and electro magnetism (copy)

Magnetism is defined as a material's ability to attract what 3 materials?

Iron, cobalt, and nickel

What is Fe?

Iron

What is Co?

Cobalt

What is Ni?

Nickel

What are the 3 classifications of magnetic materials?

Natural magnet, artificial permanent magnet, and electromagnet

What is the definition of a natural magnet?

Inherent magnetism

What is the definition of an artificial permanent magnet?

Usually hard steel artificially magnetized so it can attract iron

What is the definition of an electromagnet?

Temporary magnets produced by means of an electrical current

What are the 3 laws of magnetism?

Polarity, attraction/repulsion, and inverse square

What is the law of polarity?

All magnets have 2 poles

What is the law of attraction and repulsion?

Like poles repel, opposite poles attract

What is the inverse square law?

The force of attraction is inversely proportional to the square of the distance and directly proportional to the magnetic field strength

What is a magnetic field?

The zone of influence surrounding a magnet

What is a magnetic field made up of?

Flux lines

What are flux lines?

Invisible lines of force

If flux lines are more widely spread out, the magnetic field will be what?

Weaker

If flux lines are more spaced together, the magnetic field will be what?

Stronger

Increasing flux density will have what effect on the strength of the magnetic field?

Increase

Decreasing flux density does what to the strength of the magnetic field?

Decrease

Flux lines traveling in the same direction are what by one another?

Repelled

Flux lines traveling in the opposite direction are what by one another?

Attracted

What direction are flux lines directed?

North to south

What is the definition of permeability?

How easily a material can be magnetized

What is the definition of retentivity?

The ability of a material to resist demagnetization

What are examples of ferromagnetic materials?

Iron, cobalt, and nickel

What are examples of paramagnetic materials?

Platinum

What are examples of diamagnetic materials?

Bismuth, beryllium, and graphite

In the thumb rule, the thumb is pointing in the direction of what?

Electrical current

In the thumb rule, the fingers wrapped around the conductor will indicate what?

The direction of the flux lines around the current

A magnetic field only exists around a wire when?

When electrical current is flowing

What is a solenoid?

A coil carrying current

What is an electromagnet?

A solenoid with an iron core

What is the first of two laws Faraday stated regarding electromagnetic induction?

If a loop of wire is placed in a moving magnetic field, there will be an EMF induced in it

What is the second law Faraday stated regarding electromagnetic induction?

The strength of the EMF is determined by the rate the conductor crosses the flux lines

What are the 4 factors that determine the strength of the induced current in a conductor?

Speed at which the conductor cuts the lines of flux, strength of magnetic field, angle that lines of flux are cut, and the number of turns in the conductor

The more flux lines cut per second (faster) means what for the induced EMF?

Higher induced EMF

A greater magnetic field means what for the induced EMF?

Greater induced EMF

The closer to 90 degrees means what for the induced EMF?

Greater induced EMF

The greater number of coils means what for the induced EMF?

Greater EMF

What is EMF?

Electromotive force

What are the 3 ways to induce current or voltage in a conductor by electromagnetic induction (EMF)?

Conductor moves across a stationary magnetic field, the magnetic field may move across a stationary conductor, or change the strength of the field

Induced current flows how compared to induced EMF?

Opposite

Self-induction requires how many coils?

1

Mutual induction requires how many coils?

2