Physics Chapter 16: Electric Charge Flashcards

Questions and Answers

What is static electricity?

Magnetic fields created by moving charges

Friction produces electrical charge (correct)

Electric charge at rest (correct)

Electric current produced by batteries

How does an object become charged?

By rubbing, it possesses a net electric charge.

What are the two kinds of charges?

Positive charge and negative charge.

What is the net charge if equal amounts of opposite charge are produced?

Zero. Signup and view all the answers

What happens when charge is transferred between two objects?

One loses electrons, one gains electrons. Signup and view all the answers

How is an atom represented in terms of charge?

By atomic number and atomic mass. Signup and view all the answers

Electrons are less massive than protons and neutrons.

True Signup and view all the answers

What happens when an object is neutral?

It contains an equal amount of positive and negative charges. Signup and view all the answers

What determines the structure, properties and function of matter?

The atomic structure and bonds. Signup and view all the answers

Define an ion.

An atom that has lost or gained an electron and has a net positive or negative charge. Signup and view all the answers

What are conductors?

Materials like metals that conduct electricity. Signup and view all the answers

What are insulators?

Materials like water that do not conduct electricity. Signup and view all the answers

How does conduction charge an object?

Charge flows from one object to another when they touch. Signup and view all the answers

What does an electroscope do?

It can detect charges. Signup and view all the answers

How can charge be induced?

Through the influence of a charged object without physical contact. Signup and view all the answers

What is the net charge on a conductor?

The sum of all positive and negative charges. Signup and view all the answers

What are free charges in a conductor?

Electrons that can move about freely. Signup and view all the answers

What prevents the leaves of an electroscope from moving farther apart?

Tension force balances the electric force of repulsion. Signup and view all the answers

What happens if the charge is doubled on one object?

The force is doubled. Signup and view all the answers

What happens if the charges on both objects are doubled?

The force increases to 4 times the original value. Signup and view all the answers

What happens if the distance between charged objects is doubled?

The force decreases to 1/4 of its original value. Signup and view all the answers

What can be said about two repelling charged balls?

They are either both positive or both negative. Signup and view all the answers

What charge must a metal ball have if it is attracted to a positively charged rod?

Negative or neutral. Signup and view all the answers

What happens when two neutral conductors are connected by a wire and charged rod is brought near?

Positive charge will flow from one conductor to another due to polarization. Signup and view all the answers

According to Coulomb's law, what does force depend on?

The product of the magnitude of both charges. Signup and view all the answers

What is the superposition principle?

The net force on any charge is the vector sum of forces from all other charges. Signup and view all the answers

Where should a charged ball be placed between two positively charged balls to get zero net force?

It can either be positive or negative. Signup and view all the answers

Which particle has the largest acceleration when a proton and an electron are released?

The electron. Signup and view all the answers

What happens when moving farther away from a positive charge?

Experiences less electric force and electric field. Signup and view all the answers

What is called action at a distance?

Noncontact electrical force. Signup and view all the answers

What do we call +Q?

Source of electric field. Signup and view all the answers

What do we call -Q?

Sink of electric field. Signup and view all the answers

What happens when Q interacts with an electric field?

It produces an acceleration. Signup and view all the answers

What is the formula for electric force?

F = qE Signup and view all the answers

What is line density in an electric field?

The number of lines that cross a specific area is proportional to the intensity. Signup and view all the answers

Why can electric field lines never cross?

Electric force has a unique direction at each point. Signup and view all the answers

What is an electric dipole?

A pair of equal but opposite charges. Signup and view all the answers

What does the gravitational field do?

Produces an attractive force around the Earth. Signup and view all the answers

What is electric flux?

A scalar quantity referring to electric field passing through an area. Signup and view all the answers

What is the electric flux formula for uniform fields?

I = EAcos(theta). Signup and view all the answers

What determines the number of field lines in an electric field?

It is proportional to the charge. Signup and view all the answers

What are characteristics of conductors in electrostatic equilibrium?

Electric field inside is zero, field is perpendicular to surface, and charge is distributed on the surface. Signup and view all the answers

Study Notes

Electric Charge Fundamentals

Static Electricity: Produced via friction, resulting in electric charge; requires electric force to cause motion.
Charging Mechanism: Objects gain charge through rubbing, resulting in a net electric charge.
Types of Charges: Identified as positive and negative; unlike charges attract while like charges repel.
Charge Conservation: When one object gains charge, another loses an equal amount, maintaining a net charge of zero.

Atomic Structure and Charge

Atom Representation: Defined by atomic number (protons) and atomic mass (protons + neutrons).
Charge Neutrality: An object is neutral when it has equal amounts of protons and electrons.
Ion Formation: Atoms become ions by losing or gaining electrons, resulting in a net positive or negative charge.

Conductors vs. Insulators

Conductors: Metals like gold and silver allow free movement of charge; electrons are loosely bound to nuclei.
Insulators: Such as water, have tightly bound electrons and do not conduct electricity.
Charge Transfer: Friction can separate charges; when two materials are rubbed, charge can be transferred.

Methods of Charging

Conduction: Involves direct contact between charged and neutral objects, resulting in both acquiring the same charge.
Induction: A charged object induces a charge separation in a neutral object without direct contact, leading to polarization.

Electric Forces and Fields

Coulomb’s Law: The force between charges depends on the product of their magnitudes and the distance between them; doubling one charge doubles the force, while doubling both charges quadruples the force.
Electric Field Direction: From positive to negative charges; does not overlap, signifying that no two forces can act at the same point.

Electric Field Characteristics

Electric Flux: A measure of electric field intensity across an area, proportional to the number of field lines penetrating a surface.
Electrostatic Equilibrium: Inside a conductor, the electric field is zero; excess charge resides on the surface, and field lines are perpendicular to the surface.

Forces and Particle Behavior

Particle Acceleration: The electron experiences a greater acceleration than the proton when both are subjected to the same force due to its lower mass.
Repelling Charges: If two charged objects repel each other, they must be of the same type (both positive or both negative).

Gauss's Law and Shielding

Gauss's Law: Relates the electric field and charge enclosed within a closed surface; the number of electric field lines corresponds to the net charge.
Electrostatic Shielding: The principle stating that the electric field inside a conductor is zero when in electrostatic equilibrium.

Overall Concepts

Action at a Distance: Electric forces can act over a distance without contact.
Field Representation: Electric field lines illustrate the direction of force on a positive test charge; they cannot intersect due to unique directionality at each point.
Electrical Induction: Charging can occur by inducing a charge to move within an object without direct contact, allowing for temporary polarization effects.

By understanding these core concepts, students can grasp the principles governing electric charges and fields.

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Test your understanding of static electricity and electric charges with these flashcards. This quiz covers key concepts such as how objects become charged and the two types of charges. Perfect for students studying electric fields in physics.