Quiz questions Flashcards
What does D.C stand for?
direct current
what does A.C stand for?
alternating current
How many different versions of a.c are there?
single phase and polyphase
D.C has what type of polarities?
positive and negative
what colour is positive terminals?
red
colour of negative terminals?
black
3 major states of matter?
solid liquid gas
what is an element?
A single uncombined substance consisting of one type of atom
What is a compound?
type of atom that contains two or more elements with atoms of more than one type
Amount of electrons in the outter valence?
8
Atoms with 1-3 valence electrons?
Conductors
Atoms with 5-8 valence electrons?
Insulators
Atoms with 4 valence electrons are called what?
Semi-conductors
Smallest unit which an element can be broken down?
atom
What is the smallest unit which a substance can be broken down?
molecule
3 ways in which a body may receive a charge?
conduction, induction, and friction
Negatively charged atom?
Ion
A positive charged atom?
cation
how is piezoelectricity produced?
applying pressure
how is photovoltaic electricity produced?
by light
How is triboelectricity produced?
by friction
how is electrochemical electricity produced?
by chemical means
How is thermoelectrical electricity produced?
produced by heat
How is magnetoelectrical electricity produced?
produced by magnetism
What direction do electrons flow?
negative to positive
How far must you stay away from fallen power lines?
10 metres
how far must you be away from energized lines when operating equipment?
3-7metres
What does potential difference mean?
voltage difference
Which diagram shows the highest outage at the top and lower voltage at the bottom?
One line diagram
Which diagram is the best for the do-it-yourself hobbyist?
a wiring diagram
Which diagram is like circuit maps?
Schematic diagram
What does a multimeter measure?
AC DC voltage
AC DC amps
resistance
What are field forces?
Forces between electric charges
How many ways may a body receive a charge and what are they?
Three.
Friction, Conduction, Induction
Electricity from friction?
When two dissimilar substances are brought close to each other or rubbed together, also known as the triboelectric effect
Conduction?
When a body comes into contact with an uncharged body
Induction?
Principal of inducting a current flow in a wire when it is moved within a magnetic field
The six major categories that can be converted into energy?
Heat Light Friction Chemical Magnetism Mechanical pressure
electricity from heat?
the thermoelectric effect, when 2 dissimilar metals are heated , greater the heat the greater the emf
electricity from light?
light energy is transmitted by small particles known as photons
Electricity from magnetism?
The principle of inducting the current flow in a wire when it is moved within a magnetic field
electricity from chemical energy?
two dissimilar electrodes are inserted into a electrolyte with interacts with the metals, causing electrons to transfer
Electricity from Mechanical Pressure?
Interacting of electrostatic and mechanical stresses within certain crystals
What is the difference between electrical power and energy?
Energy is the ability to do or store work and power is the rate of doing work
Ohms law states that current is directly proportional to the _____, and inversely proportional to the _________?
voltage and resistance
formula for coulomb’s law of electrostatic charges?
F = K x Q1 x Q2 / D2
What is a coulomb?
it is equal to the quantity of electricity conveyed in one second by a current of one ampere
One ampere is equal to what?
6.24 x 10 18 power , electrons per second and is also equal to one coulomb per second
What are the 4 factors used to determine the resistance of a piece of wire?
- M material it’s made of
- A cross sectional area
- L conductor length
- T it’s temperature
“ohms per mil-ft” of copper and aluminum?
copper is 10.4
aluminum is 17
When an atom losses an electron , the atom becomes?
positive
