CVT 102

Question 1

What is matter?

Answer 1

Anything made of atoms and molecules; anything that has mass.

Question 2

How do electron fields influence conductivity?

Answer 2

The high-energy free electrons escape their valence shell (leaving it as an ion) and can be influenced to flow to more positive charges, creating a current through conductive material.

Question 3

What are the charges of a proton, neutron, and electron?

Answer 3

Proton +
Neutron - neutral
Electron -

Question 4

What is the most commonly used metal in electrical applications? Why?

Answer 4

Copper - highly conductive and cheap

Question 5

What is a conductor?

Answer 5

Materials that readily allow current. They have a large number of free electrons. Eg Most Metals - Silver best follower by Copper (most common used in circuits.(1-3 valence e-)

Question 6

What is a semiconductor?

Answer 6

Carry less current than Conductors because they have fewer free electrons. Eg Silicon.

Question 7

What is an insulator?

Answer 7

Nonmetallic material s that are POOR conductors of electric current. Used to prevent current where it is not wanted. They have NO free electrons in their structure. Valence electrons are BOUND to the nucleus and not considered “free”. Eg Glass, porcelain, teflon etc.

Question 8

What is a coulomb?

Answer 8

Total charge possessed by

6.25 x 10^18 electrons. A set number of electrons.

Question 9

The region in which a CHARGE (- or +) experiences

an electrical force is called an:

Answer 9

electric field

Question 10

• A force exists between a positive and negative charge.
• A certain amount of E must be exerted IN THE FORM
OF WORK to overcome this force and MOVE the
charges a given distance apart.
• So all OPPOSITE charges possess a certain
POTENTIAL ENERGY because of this SEPARATION.
• This difference in potential energy PER CHARGE is the
POTENTIAL DIFFERENCE or ____________.!

Answer 10

voltage

Question 11

How does a volt relate to a joule and coulomb?

Answer 11

Volt equals joules per coulomb. So 6 V would give 6 joules of energy to each coulomb moved.

V = W/Q

Question 12

What is voltage (V)?

Answer 12

The driving force in an electric circuit. Establishes current. V

Question 13

What is current (I)?

Answer 13

Free movement of electrons. VOLTAGE provides energy that allows them to move. Allows for WORK to be done.

Question 14

What happens to the random movement of free electrons when a voltage is applied across a conductive or semiconductive material?

Answer 14

Electrons flow from negative to positive in a CURRENT.

Question 15

What is an ampere (A)?

Answer 15

A unit of CURRENT.
One ampere (1A) is the amount of current that exists when one
coulomb (charged carried by 6.25 x 10^18 e-) of charge moves
through a given cross sectional area in one second.

Question 16

What is RESISTANCE (R)? Units?

Answer 16

• The property of a material that restricts
the flow of electrons.
• With current the moving free e-
occasionally collide with atoms.
• Collision causes loss of E, restricting their
motion. More collisions = greater loss of
E.
• Material determines the amount of
RESTRICTION to the movement of the e-.
- OPPOSES CURRENT!
- Ohms.