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AC Theory Lvl. 1 L1-5 assignment exam with complete solutions 2024_2025
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AC Theory Lvl. 1 L1-5 assignment exam with complete solutions 2024_2025
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AC Theory Lvl. 1 L1-5 assignment examwith complete solutions 2024/2025
The direction of induced ? flow through a conductor is determined by the
direction of the magnetic field surrounding the conductor and the direction the
conductor is traveling through the magnetic field. - ANSWER-current
1Q1
Whenever a conductor cuts through magnetic lines of flux, a ? is induced into the
conductor. - ANSWER-voltage
1Q1
When no current flows in a conductor, free electrons move ? , and their magnetic
fields cancel. - ANSWER-at random
1Q2
Whenever current flows through a conductor, a ? is created around the
conductor. - ANSWER-magnetic field
1Q1
When current flows in a conductor, a magnetic field is produced. As free
electrons move in one direction, their individual magnetic fields ? . - ANSWER-
add together
1Q3
The important factors needed for generation of an induced voltage are a
conductor, a magnetic field, and ? . - ANSWER-relative motion
1Q4
,As current flow decreases, the magnetic field surrounding the conductor will ? . -
ANSWER-Decreases
1Q5
As the current passing through a coil increases, the magnetic field around the
coil will ? . - ANSWER-Increase
1Q5
When a conductor moves through a stationary magnetic field an EMF is induced,
but when the magnetic field moves and the conductor remains stationary no EMF
is induced. - ANSWER-False
1Q6
Whenever an electric current flows through a conductor, a magnetic field is
formed ? the conductor. - ANSWER-Around
1Q7
? Law states that an induced voltage or current opposes the motion that causes
the induced voltage or current. - ANSWER-Lenz's
1Q8
Inductors always oppose a change of ? . - ANSWER-current
1Q9
Counter Electromotive Force is sometimes called back EMF, and CEMF is ? out-
of-phase with the applied voltage. - ANSWER-180 degrees
1Q10
CEMF ? the applied EMF when current is increasing and ? the applied EMF when
current is decreasing. - ANSWER-subtracts from / adds to
1Q11
Which items listed below are factors that work in combination to affect the
inductance produced by an inductor.
I. Cross sectional area of the core
II. Number of turns of wire
III. Permeability of the core material
IV. Spacing between the turns
V. All the Above - ANSWER-V.
1Q12
, The rate of current change in an inductive circuit can be described as a(n) ?
curve. - ANSWER-exponential
1Q14
How many time constants does it take for current to reach its maximum value in
an inductive circuit? - ANSWER-5
1Q15
At what percentage is the current after one time constant when the circuit is first
energized? - ANSWER-63.2%
1Q16
At what percentage is the current after two time constants? - ANSWER-86.4%
At what percentage is the current after three time constants? - ANSWER-94.9%
At what percentage is the current after four time constants? - ANSWER-98.1%
At what percentage is the current after five time constants? - ANSWER-100%
The unit of inductance is the ? , and inductance is represented by the letter ? . -
ANSWER-henry / L
1Q17
If a change of one ampere in one second causes one volt to be induced, you have
? of inductance. - ANSWER-one henry
1Q18
In high frequency applications, ? inductors are used because of eddy current loss
and hysteresis loss in the core material. - ANSWER-air core
Note: Remember from earlier chapters, that some core materials such as soft iron
are affected when used at higher
frequencies. The eddy current losses and hysteresis loss make soft iron a poor
choice for use in high frequency
applications.
1Q19
What is the formula for inductance? - ANSWER-L = ( 0.4 * pi * N^2 *A* µ)/(l)
Wherein:
A = Cross sectional area of the core
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