W8 Electrical & Fire Safety Flashcards
(87 cards)
What is the SI unit of Electrical Charge?
A) volt
B) coulomb
C) watt
D) Hz
B
What does coulombs law state?
Like charges repel each other and opposites attract (inversely to square root of their distance)
What is electricity?
A) power
B) protons
C) flow of electrons
D) neutrons
C
T/F. Charges have the ability to move.
True!
Electrical current (I) defines charges ability to move using SI unit ampere (AMP; A)
1Amp = 1coulomb/sec
Electrical conductors (select all that apply)
A) Charges do not move freely
B) Metal
C) Charges move freely
D) Hold on to static charge
E) Don’t hold on electrons tightly
B, C, E
Electrical conductors are materials in which charges can easily move. They are made of atoms that do not hold onto electrons tightly. They are METAL (eg. Copper)
Electrical insulators (select all that apply)
A) Charges do not move freely
B) Metal
C) Charges move freely
D) Hold on to static charge
E) Don’t hold on electrons tightly
A, D
Electrical insulators are material in which charges cannot freely move. They hold on to significant static charge and are NON-METAL
What does Ohm’s law measure?
Resistance to flow & conductance
Ohm’s law states the potential flow of electric charge is proportional to the actual current after accounting for ______.
resistance
Resistance is a ratio of
A) power to charge
B) Current to energy
C) voltage to current
D) none of the above
C
Resistance is a ratio of voltage to current
R = volt/electrical current
R= V/I
T/F. Conductance is the same measure of resistance.
False!
Conductance is the RECIPROCAL of resistance
G = 1/R
What is the SI unit for electrical potential energy? (Read carefully)
A) Joule
B) Volt
C) Ampere
D) Coulomb
A
What is the SI unit for electrical potential?
A) Joule
B) Volt
C) Ampere
D) Coulomb
B
T/F. A circuit exists when a charge is able to flow around a closed path
True
In a DC circuit, current flows in _______ direction
One
Ex. Batteries
In an AC circuit, current flow ___________ direction
periodically changes
Ex. wall outlets and AC generators
What is the current flow for a series circuit?
A) more than one path
B) single path
C) varying path
D) no path
B
Series circuit has one path current flow.
Think + end of one battery to - end of another battery and keeps going.
Voltages and resistances in a series circuit are ________.
Additive
Think + end of battery to - end of battery to battery.
(+)——(-)——-(+)——(-)——(+)
What is the current flow for a parallel circuit?
A) more than one path
B) single path
C) varying path
D) no path
A
A parallel circuit has a current with more than one path and will have junctions where wires connect.
Resistors are connected in a parallel to create a UNIQUE CURRENT
Ex: Household circuits (electricity can run through any individual appliance without requirement that every appliance be turned on at the same time)
Energy = ______ x _______.
Power x Time
Define power
rate at which energy is expended or consumed
What is the SI unit of power?
A) Joule
B) Watt
C) Ampere
D) Coulomb
B) Watt
Current is the rate of flowing _______.
Charges
Semiconductors are prepared mostly from?
A) Metals
B) Non-metals
C) Semi-metals
D) None of the above
C) Semi-metals (mostly silicon)
Semiconductors have the ability to control conductivity by adding small amounts of impurities called __________.
Doping agents