The flashcards below were created by user
on FreezingBlue Flashcards.
An atom is the smallest possible particle
that retains the characteristic of which of
the following substances?
If light energy collides with an orbiting
electron, what happens to the electron?
The electron will jump to an orbit further from the nucleus
When an atom gains or loses an electron,
which of the following terms applies?
What is the main difference between
conductors, semiconductors, andinsulators?
The number of free electrons
Which of following actions describes the
easiest way to accumulate a static electric
Friction between two insulators
Ferromagnetic materials have which of the
They are relatively easy to magnetize
A material with low reluctance and high
permeability such as iron or soft steel is
used to make what type of magnet?
Weber,s theory of magnetism assumes that
magnetic material is composed of
tiny molecular magnets
According to the domain theory, if an atom
with 26 electrons has 20 electrons spinning
counterclock-wise, the atom is considered
When directed drift takes place, at what
speed does the effect take place?
186,000 miles per second
Carbon resistors have which of the
The resistance value changes with age
What is the total number of connections on
(a) a rheostat and (b) a potentiometer?
(a) Two (b) three
The property of inductance offers
opposition to which of the following
Changes in current
What is the symbol for inductance?
What is the unit of measurement for
What physical property is similar to
According to Lenz's Law, the induced
emf produced by a change in current in
an inductive circuit tends to have what
effect on the current?
It opposes either a rise or a fall in Current
The direction of the induced voltage in 3. soft iron an inductor may be found by application
of which of the following rules?
The left-hand rule for generators
How are inductors classified?
By core type
Which of the following factors will
NOT affect the value of inductance of a
Why do large diameter coils have
greater inductance than smaller diameter
coils, all other factors being the same?
Large diameter coils have more wire and thus more flux
A soft iron core will increase inductance
because it has which of the following
Low permeability and high Reluctance
An increase in the permeability of the
core of a coil will increase which of the
following coil characteristics?
If a coil is wound in layers, its
inductance will be greater than that of a
similar single-layer coil because of a
Regardless of the method used,
inductance of a coil can ONLY be
increased by increasing what coil
What is the symbol used to denote the
basic unit of measurement for
Inductors experience copper loss for
Because all inductors have resistance which dissipates power
What term applies to the power loss in
an iron core inductor due to the current
induced in the core?
Power consumed by an iron core
inductor in reversing the magnetic field
of the core is termed as what type of
Capacitance and inductance in a circuit
are similar in which of the following
Both cause the storage of energy
Capacitance is defined as the property of
a circuit that
opposes a change in voltage
Electrostatic lines of force radiate from
a charged particle along what type of
Which of the following characteristics
of a capacitor can be varied WITHOUT
altering its capacitance?
Thickness of the dielectric
The maximum voltage that can be
applied to a capacitor without causing
current flow through the dielectric is
Which, if any, of the following
conditions may cause a capacitor to
suffer power losses?
Rapid reversals in the polarity of the line
voltage applied to a capacitor will cause
what type of capacitor power loss?
Has an oxide film Dielectric
Can be adjusted by a
A polarized capacitor
Has a waxed paper dielectric
An adjustable capacitor with a mica dielectric
Which of the following defines transformer action?
The transfer of energy from one circuit to another through electromagnetic action
Which of the following is NOT a necessary element in a basic transformer?
A magnetic shield
The two types of transformer cores most
commonly used are the shell-core and
What is the principal difference between
a high-voltage transformer and a lowvoltage
A high-voltage transformer has more insulation between the layers of windings than does a low-voltage transformer
What term applies to the current in the
primary of a transformer that creates the
In the primary of a transformer, what
opposes the current from the source?
The self-induced emf
Power lost in realigning domains
Power dissipated by the resistance of the windings
Power loss caused by random core currents
Used above 20 kHz
The secondary is a tapped primary
Used to deliver voltage from a source to a load
Can be used to match impedance in a sound system