PHY 102 - General Physics II: Electrostatics

Flashcards for reviewing Electrostatics and related concepts from Physics 102 lecture notes.

Forces

Forces are fundamental interactions that cause objects to change their state of motion or shape.

Electrostatics

The study of electricity in which electric charges are static (not moving).

Magnetic Effect

Collection of dust on television screen.

Magnetic Effect

A plastic comb rubbed with hair attracts piece of paper.

Heating Effect

A woolen jumper worn over nylon blouse gives sparks when taken off.

Chemical Effect

The flowing movement of flammable liquid like gasoline inside pipe.

Neutral Body

In an unchanged (neutral) body, the number of electrons is equal to the number of protons.

Conductors

Materials in which free electrons are not strongly attached to an atom and are thus free to move about from one atom to another. Examples include metals such as silver, copper, aluminum.

Insulators

Materials in which electrons are bound to the atoms and hence cannot move from one atom to atom. Examples include wood, plastic, glass, and silk.

Dielectric

An insulator or nonconductor of electricity.

Dielectric Effect

The ratio of the capacitance of a capacitor with a dielectric between the plates to the capacitance of a capacitor without a dielectric between the plates.

Dielectric Constant (κ)

A constant that accounts for the effect of the dielectric between the plates of a capacitor, defined as the ratio of the capacitance with a dielectric to the capacitance with a vacuum.

Charging by Friction

When two uncharged objects rub together, some electron from one object can move onto the other object. The object that gains the electron becomes negatively charged and the object that loses electrons becomes positively charged.

Charging by Conduction

The transfer of electrons from charged objects to other objects by direct contact.

Charging by Induction

The movement of electrons to one part of an object that is caused by the electric field of a second object.

Coulomb's Law

The force F of repulsion or attraction between two charges Q1 and Q2 is proportional to the product of the two charges and inversely proportional to the square of the distance r separating them.

Superposition Principle

Describes how to calculate forces when multiple charges are present, stating that the net electrostatic force on a charge is the vector sum of the forces from all other charges.

Electric Field

The region of space in which the force due to the charge can be experienced.

Electric Field Intensity

The strength of electric field at a point, defined as the force experienced per unit positive charge at that point E = F/Q.

Electric Line of Force

Indicates the direction of the force on a positive charge placed in an electric field and the direction of the electric field intensity at that point.

Electric Field Lines

A graphical representation of the electric field, showing direction, density, origin, and termination.

Electric Potential (V)

The energy transformation in bringing a unit positive charge from infinity to that point against the action of the field.

Equipotential Surface

Points in the field that have the same potentials and can be imagined as lying on a surface. When charges move on such a surface, no energy change occurs and no work is done.

Gauss's Theorem

The flux through a closed surface is equal to the net charge enclosed by the surface divided by the permittivity.

Capacitor

Any pair of conductors separated by an insulating material that can store charges or electrical energy.

Capacitance (C)

The constant of proportionality between charge and potential difference in a capacitor Q = CV.

Ohm's Law

States that the current flowing through a metallic conductor is directly proportional to the potential difference and inversely proportional to the resistance I = V/R.

Resistance (R)

The property of a conductor that determines the amount of current it can permit under a given potential difference.

Resistivity (ρ)

The proportionality constant relating resistance to length and cross-sectional area.

Conductance

The reciprocal of resistance.

Conductivity

The reciprocal of the resistivity.

Electric Power

The rate at which electrical work is done i.e., P=VI.

Electromotive Force (EMF)

Voltage of an active component when it is not delivering any voltage to any load (external circuit).

Potentiometer

An instrument that measures potential difference more accurately.

Wheatstone Bridge

Equipment that offers an accurate method for comparing resistance especially of moderate magnitude and also for calculating of an unknown resistance.

Meter Bridge

Practical version of the Wheatstone bridge, primarily sue of the meter bridge is the measurement of resistance.

Ammeter

Modified galvanometer that measures current.

Voltmeter

Modified galvanometer that measures voltage.

Galvanometer

The basic meter for direct current measurements that detects small currents or small potential differences.

Alternating Current (AC)

A current which varies periodically.

Capacitive Reactance

The opposition to current flow in a capacitive circuit.

Inductive Reactance

The opposition to current flow in an inductive circuit.

Impedance

Total opposition to current flow in an AC circuit, combining resistance and reactance.

Resonance

Condition in an RLC circuit where maximum AC current flows.

Root-Mean-Square (RMS)

The steady direct current which converts electrical energy to other forms of energy in a given resistance at the same rate at the a.c.

Power Factor

The average power divided by the apparent power in an AC circuit.