Magnetism and Magnetic Fields

A comprehensive set of flashcards covering key concepts from the lecture on magnetism and magnetic fields.

What is magnetism?

One of the fundamental forces critical in everyday life and industry.

What primary particle is magnetism based on?

Electrons.

What is electron spin?

A quantum mechanical property of electrons that can be either +/- half.

What creates magnetism in materials?

Unpaired electrons.

What are diamagnetic materials characterized by?

Only paired electrons; weakly repelled by magnetic fields.

What are paramagnetic materials characterized by?

Unpaired electrons with random spins; weakly attracted to magnetic fields.

What are ferromagnetic materials?

Materials with stable, non-random spin that can be permanent magnets, such as iron.

What are magnetic dipoles?

The basic units of magnetism that have north and south poles.

What happens when you cut a magnet in half?

It results in two dipoles, each with a north and south pole.

What is the direction of magnetic field lines?

They conventionally run from North to South.

What unit measures magnetic field strength?

Tesla (T).

What is the equation for calculating magnetic field (B) generated by a current (I)?

B = µ₀I / (2πr).

What does the right-hand rule help predict?

The direction of the magnetic field around current-carrying wires.

What does a dot in a circle represent in magnetic field notation?

Field coming out of the page.

What does an X in a circle represent in magnetic field notation?

Field going into the page.

What is the Lorentz force vector equation?

FB = qvB sin(θ).

What does the Lorentz force depend on?

Charge (q), velocity (v), magnetic field (B), and angle (θ) between the particle’s velocity and the magnetic field.

When is the magnetic force maximized?

When the particle’s motion is perpendicular to the magnetic field.

When is the magnetic force minimized?

When the particle’s motion is parallel to the magnetic field.

What is the variation for a current-carrying wire for magnetic force?

FB = ILB sin(θ).

What do thumb, fingers, palm, and back of hand represent in Right-Hand Rule #2?

Thumb: direction of current; Fingers: direction of magnetic field; Palm: force on a positive charge; Back of hand: force on a negative charge.

What does a magnetic field cause in charged particles?

Circular motion due to perpendicular force.

What is the simplified equation for the radius of circular motion of charged particles?

r = mv / qB.

What does the Lorentz force combine?

Electric force (E-fields) and magnetic force (B-fields) on a charge.

In the context of magnetic fields, what is 'r'?

The radius of the path of a charged particle.

What effect does the angle between a particle's trajectory and the magnetic field have?

It affects the magnetic force experienced by the particle.

What happens if a charged particle moves through both electric and magnetic fields?

The net force can be determined by combining the effects of both fields according to the Lorentz force equation.

How are diamagnetic materials affected by magnetic fields?

They are weakly repelled.

How does a ferromagnetic material behave in a magnetic field?

It can act as a permanent magnet due to stable non-random spin.

What is the importance of the right-hand rule in electromagnetism?

It helps predict the direction of the magnetic field created by a current.

What does the term 'vector quantity' refer to?

A quantity that has both magnitude and direction.

What does a charge need to create a magnetic field?

The charge must be in motion.

What is indicated by a magnetic field at a distance from the source?

The strength and direction of the field decrease with distance.

What is the SI unit of magnetic field strength?

Tesla (T).

When can you use the right-hand rule with wires?

When predicting the magnetic field direction around current-carrying wires.

What phenomenon is integral to understanding electromagnetism?

The Lorentz force.

In charged particle motion, what does 'F = m(v^2/r)' represent?

The relationship between mass, velocity, and radius in circular motion.

What is the angular acceleration formula associated with charged particles in magnetic fields?

a = v^2/r.

What do stable spins in ferromagnetic materials allow for?

The creation of permanent magnets.

Why is it critical to know the charge of a particle when discussing magnetic forces?

The force experienced by a particle depends on its charge.

How does the strength of a magnetic field influence force on a charged particle?

The force is directly proportional to the magnetic field strength.

What types of materials have unpaired electrons?

Paramagnetic and ferromagnetic materials.

What impact do unpaired electrons have on magnetism?

They create stronger magnetic fields due to their random spins.

What does a magnetic field cause in terms of particle paths?

It induces circular or spiral paths for moving charges.

What is the effect of increased current in a wire on the magnetic field strength?

The magnetic field strength increases.

In practical applications, how is the radius of charged particle paths utilized?

It's used in devices like mass spectrometers to infer particle mass and velocity.

What is the effect of cutting a magnet?

It creates two smaller magnets, each with its own north and south poles.

What does 'FB = q(E + vB)' represent?

The total force on a charged particle in both electric and magnetic fields.

What kind of materials are weakly attracted to magnetic fields?

Paramagnetic materials.

Which material is weakly repelled by magnetic fields?

Diamagnetic materials.

What do magnetic field lines show?

The direction and strength of the magnetic field.

What happens to magnetic field strength as you move away from the source?

It decreases with distance.

Is the magnetic field around a wire straight or curved?

Curved.

How are the properties of magnets important in industry?

They play critical roles in motors, generators, and magnetic storage.

How do you establish the direction of a magnetic field?

Using the right-hand rule.

What is the relationship between charge motion and magnetic fields?

Moving charges create magnetic fields.

When is the magnetic force zero?

When the particle's motion is parallel to the magnetic field.

What type of electron pairing cancels out magnetic properties?

Paired electrons.

What field does a current-carrying wire generate?

A magnetic field.

What does the angle θ stand for in the Lorentz force equation?

The angle between the particle’s velocity and the magnetic field.

In terms of fields, what does 'FB = ILB sin(θ)' represent?

The magnetic force experienced by a current-carrying wire.

What is a critical aspect of understanding magnetism and magnetic fields?

Identifying the orientation of magnetic fields and forces.

What is the name of the phenomenon where an electric charge creates a magnetic field?

Electromagnetism.

What is one everyday application of magnetic principles?

Refrigerator magnets.

What is the relationship between magnetic field lines and strength?

The density of lines indicates the strength of the field.

What determines the motion of charged particles in magnetic fields?

The Lorentz force governing their path.

What concept allows us to visualize and navigate magnetism in physical spaces?

Magnetic field representation with notation like dots and crosses.

What signifies a charged particle's positive or negative nature in the context of forces?

The direction of the induced force as per the right-hand rule.

Why is understanding the right-hand rule essential?

It helps predict interactions between current, magnetic fields, and resulting forces.