Fundamental Interactions and Electric Charges

These flashcards cover key concepts, definitions, and principles from the lecture on electric charges and fields, emphasizing fundamental interactions, properties of electric charge, and the behavior of electric forces.

What are the four fundamental interactions of the Standard Model?

Gravity, Electromagnetism, Weak Interaction, Strong Interaction.

What is the nature of the electric force?

Acts over a distance without contact, is attractive or repulsive, decreases with distance.

What is the electric field strength formula?

E = ke * Q / r^2, where ke is Coulomb's constant.

What does Coulomb's Law describe?

The electric force between two point charges, proportional to the product of their charges and inversely proportional to the square of the distance between them.

What are the properties of electric charges?

They are quantized, conserved, and have the SI unit of Coulombs (C).

Who proposed the concept of positive and negative electric fluids?

Benjamin Franklin.

Define electric dipole moment.

The product of the charge and the distance separating the charges in an electric dipole.

What happens to electric field lines around positive and negative charges?

They start at positive charges and end at negative charges.

What effect does distance have on the electric force?

The electric force decreases with increasing distance.

What is the average volume charge density defined as?

The total charge per unit volume in a given region.

How is electric field strength related to force and charge?

E = F/q, where E is the electric field, F is the force, and q is the charge.

What is the significance of the elementary charge?

It is the smallest unit of electric charge, equivalent to approximately 1.602 x 10^-19 C.

What distinguishes conductors from insulators?

Conductors allow free movement of charge (electrons), while insulators restrict charge movement.

How do electric forces relate when multiple charges are involved?

Electric forces obey the superposition principle.

What is the torque on an electric dipole in a uniform electric field given by?

τ = p × E, where p is the dipole moment and E is the electric field.

What is a property of electric field lines?

They cannot cross each other.

What influences the density of electric field lines?

The strength of the electric field.

What is charge relaxation time?

The time it takes for charge to redistribute in a material.

What are semiconductors?

Materials with properties between conductors and insulators, such as silicon and germanium.

What is the inverse-square law as it pertains to electric and gravitational forces?

Both forces decrease with the square of the distance between two point sources.

What is electric polarization by induction?

The process of separating charges within an object without direct contact with a charged body.

What happens when a charged particle moves through a uniform electric field?

It experiences a constant force due to the electric field, resulting in uniform acceleration.

What is the role of torque in electric dipoles?

It aligns the dipole with the electric field.