Chapter 8.6 Electric Current

Question 1

What is an electric current?

Answer 1

Electric current is a flow of charged particles

Question 2

What are conductor electrons?

Answer 2

Charge carriers: one or more electrons from each atom are free to move throughout the atomic lattice.

Question 3

In fluids, what can constitute the flow of an electric charge?

Answer 3

Positive Ions and Electrons

Question 4

Do protons more in a solid?

Answer 4

No

they are bound within the nuclei of atoms and are in fixed positions

Question 5

Where are electrons located in matter?

Answer 5

Every bit of matter, wires included, contains enormous numbers of electrons that swarm about in random directions.

Question 6

When does an electric current occur?

Answer 6

When a source of voltage sets the electrons that are naturally in matter into motion, you get an electric current

Question 7

What is an Ampere?

Answer 7

The rate of electrical flow is measured in amperes.

It’s the rate of flow of 1 Coulomb of charge per second.

Question 8

What is the drift speed of electrons in a typical circuit?

Answer 8

The speed of electrons as they drift through a wire is surprisingly slow.
It’s much less than 1cm/sec

Question 9

How fast does the electrical signal travel?

Answer 9

At the speed of light
As soon as you close a switch in an electric circuit, the battery sends an electric field instantaneously through all parts of the circuit.

Question 10

How fast is the electric field in the wire established?

Answer 10

At the speed of light

Question 11

What is the net charge of a current carrying wire?

Answer 11

It has almost no net charge.
Under ordinary conditions, the number of electrons and protons balance, so whether a wire carries a current or not, the net charge of the wire is normally zero at every moment.

Question 12

How does electron circulation work with a battery?

Answer 12

The negative terminal of the battery repels the negative electrons and they move towards the positive terminal because of their attraction to positive charge

Question 13

What is the direction of electrical current?

Answer 13

It’s from positive to negative-

From the positive battery terminal, through the circuit, and toward the negative terminal

Question 14

Where do flowing electrons get their energy from?

Answer 14

Chemical reactions in a battery.
The electrons then deliver that energy to parts of the circuit, and then return to the battery with no energy before getting reenergized

Question 15

What are electric conductors?

Answer 15

Substances (like metal) where electrons are loose enough to flow easily

Question 16

Electric Insulators

Answer 16

Substances (like rubber or plastic) where the atoms hold their electrons tightly

Question 17

Is current “used up” in an electrical circuit?

Answer 17

No

The quantity that is used up in a circuit is not current, but energy

Question 18

What is the difference between charge flowing through a circuit and voltage placed/impressed across a circuit?

Answer 18

Charge flows through a circuit because of an applied voltage across the circuit.
Voltage doesn’t flow or go anywhere
Charge is what moves
Voltage produces a current, which makes the charge moves

Question 19

What does voltage produce in a complete circuit?

Answer 19

Voltage produces a current (making charges move) through a complete circuit

Question 20

What is Voltage?

Answer 20

Voltage is the pressure from an electrical circuit’s power source that pushes charged electrons (current) through a conducting loop, enabling them to do work such as illuminating a light. In brief, voltage = pressure, and it is measured in volts

Question 21

Direct Current

Answer 21

Charges flowing in one direction

Battery produces direct current in a circuit because the terminals of the battery always have the same sign

Question 22

In a battery operated circuit, how do electrons move?

Answer 22

They move from the repelling negative terminal toward the attracting positive terminal, and they always move through the circuit in the same direction

Question 23

What is an Alternating Current?

Answer 23

Electrons in the circuit are moved first in one direction and then in the opposite direction, alternating to and fro about relatively fixed position.

Question 24

How does an alternating current occur?

Answer 24

It’s accomplished in a generator or alternator by periodically switching the sign at the terminals.

Question 25

What are the benefits of Alternative Current (AC)

Answer 25

electric energy in the form of ac can easily be stepped up to high voltage to be transmitted great distances with small heat losses, then stepped down to convenient voltages where the energy is consumed.

Question 26

What is a diode?

Answer 26

An electronic device that allows electron flow in one direction only

Question 27

What is a light-emitting diode?

Answer 27

LED- photons are emitted when electrons cross a “band gap” in the device