Unit 7: Electrical Fires and Building Electrical Systems

Question 1

The requirement for ignition is that the heat

transfer from the electric source be ___________________

Answer 1

maintained long enough to bring the adjacent
fuel up to its ignition temperature, with air
present to allow combustion

Question 2

“The physical phenomena arising from the behavior
of electrons and protons that is caused by the
attraction of particles with opposite charges and the
repulsion of particles with the same charge.”

Answer 2

Electricity

Question 3

The flow of electrons due to a difference in
energy potential between two points on a
conductor.

Answer 3

Electricity

Question 4

Terms

Answer 4

• Voltage (V) or electromotive force (E).
• Current (I) or amperes or amps (A).
• Power (P) or watts (W).
• Resistance (R).
• Inductance (L).

Question 5

•   All matter is made of atoms.
•   Protons + neutrons = nucleus.
•   Electrons form valance rings.
•   Number of electrons = number 
of protons. Outer ring has one to 
eight electrons.
•   One to two electrons in outer ring = 
unstable ring (conductor).
•   Examples: silver, copper, gold, aluminum.

Answer 5

Atomic Theory

Question 6

•   Four electrons in outer ring = 
              semiconductor.
•   Resistance varies with temperature.
•   Increased temperatures 
               lead to decreased resistance.
•   Elements are silicon 
               and germanium.
•   Used in transistors and diodes.

Answer 6

Electrons

Question 7

•   Seven to eight electrons in the outer ring = 
stable ring (insulator).
•   Examples include various carbon 
molecules such as rubber, plastics and 
wood.
•   Movement of electrons from one atom to 
another is known as electricity.
•   Energy is required to initiate 
and continue this movement.

Answer 7

Electron structure

Question 8

• Energy is transformed during this
movement to heat and magnetism.
• Heat and magnetism always accompany
electron flow in some amount.

Answer 8

..

Question 9

What always accompanies electron flow?

Answer 9

Heat and magnetism

Question 10

What is the Maximum “harmless” current.

Answer 10

5 Milliamps

Question 11

Equipment
must be ___________________ before examination,
preventative maintenance or servicing is performed.

Answer 11

locked out and tagged out

Question 12

“The physical phenomena arising from the behavior
of electrons and protons that is caused by the
attraction of particles with opposite charges and the
repulsion of particles with the same charge.”

Answer 12

Electricity

Question 13

Voltage______ or electromotive force (E).

Answer 13

V

Question 14

Current ______ or amperes or amps (A).

Answer 14

I

Question 15

Power _______ or watts (W).

Answer 15

P

Question 16

Has weight and takes up space.

Answer 16

Matter

Question 17

When current flows, a _____________ is

generated.

Answer 17

A magnetic field

Question 18

•   Materials that allow current 
to flow freely with minimal 
resistance.
•   Copper and aluminum are 
two of the most recognized; 
both are used in electrical 
systems.
•   Gold and silver are also 
used, usually at point of 
contact.

Answer 18

Conductors

Question 19

•   They work the opposite of conductors; they 
oppose or stop the flow of current.
•   Some insulators are 
glass, porcelain, air and 
pure water.
•   However, a high enough 
voltage may defeat the 
insulator.

Answer 19

Insulators

Question 20

•   Electrical pressure that moves 
electrons through the conductor, 
known as electromotive force.
•   Shown in formulas 
as E.

Answer 20

Voltage

Question 21

Current is also referred to as

Answer 21

Amperes

Question 22

The rate at which electrons flow through a

conductor. Shown in formulas as_________ Measured in amperes (amps).

Answer 22

“I” (intensity)

Question 23

• Opposition to current flow.
• Shown in formulas as “R.”
• Measured in ohms — Greek Omega Ω
.

Answer 23

Resistance

Question 24

• Quantitative measurement of work done
consumed in an electrical circuit.
• Power is a larger issue over
a period of time.

Answer 24

Watts (W) or kilowatts (kW)

Question 25

Hydraulic Electrical
Water/Fluid Electrons
Pump Generator
Pressure Voltage
Pounds per square inch (psi) Volts
Flow Current
Gallons per minute (gpm) Amperes
Friction loss Resistance

Answer 25

.

Question 26

– Mechanically or chemically generated.
– Chemical = batteries or photovoltaic.
– Mechanical = generator.
– Electrons flow in one direction only.
– Positive and negative terminals on
equipment.

Answer 26

DC

Direct Current