-
An atom is the smallest possible particle
that retains the characteristic of which of
the following substances?
A compound
-
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?
Ionized
-
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
charge?
Friction between two insulators
-
Ferromagnetic materials have which of the
following qualities?
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?
Temporary
-
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
to be
magnetized
-
When directed drift takes place, at what
speed does the effect take place?
186,000 miles per second
-
Carbon resistors have which of the
following disadvantages?
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
quantities?
Changes in current
-
What is the symbol for inductance?
L
-
What is the unit of measurement for
inductance?
Henry
-
What physical property is similar to
Inductance
Inertia
-
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
coil?
Conductor tensility
-
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
characteristics?
Low permeability and high Reluctance
-
An increase in the permeability of the
core of a coil will increase which of the
following coil characteristics?
Magnetic flux
-
If a coil is wound in layers, its
inductance will be greater than that of a
similar single-layer coil because of a
higher
flux linkage
-
Regardless of the method used,
inductance of a coil can ONLY be
increased by increasing what coil
characteristic?
Flux linkage
-
What is the symbol used to denote the
basic unit of measurement for
inductance?
H
-
Inductors experience copper loss for
what reason?
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?
Eddy-current loss
-
Power consumed by an iron core
inductor in reversing the magnetic field
of the core is termed as what type of
loss?
Hysteresis loss
-
Capacitance and inductance in a circuit
are similar in which of the following
ways?
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
lines?
Straight lines
-
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
called
working voltage
-
Which, if any, of the following
conditions may cause a capacitor to
suffer power losses?
Dielectric hysteresis
-
Rapid reversals in the polarity of the line
voltage applied to a capacitor will cause
what type of capacitor power loss?
Dielectric-leakage
-
Has an oxide film Dielectric
Electrolytic
-
Can be adjusted by a
screw setting
Trimmer
-
A polarized capacitor
Electrolytic
-
Has a waxed paper dielectric
Paper
-
An adjustable capacitor with a mica dielectric
mica
-
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
the
hollow-core
-
What is the principal difference between
a high-voltage transformer and a lowvoltage
transformer?
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
magnetic field?
Exciting current
-
In the primary of a transformer, what
opposes the current from the source?
The self-induced emf
-
Power lost in realigning domains
Hysteresis loss
-
Power dissipated by the resistance of the windings
Copper loss
-
Power loss caused by random core currents
Eddy-current loss
-
Used above 20 kHz
Radio-Frequency
-
The secondary is a tapped primary
Autotransformer
-
Used to deliver voltage from a source to a load
Power
-
Can be used to match impedance in a sound system
Audio-Frequency
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