Induction Conceptual Analysis Homework. For each statement, decide whether it is
ID: 1309337 • Letter: I
Question
Induction Conceptual Analysis Homework.
For each statement, decide whether it is always true, always false or true in certain
circumstances. State which case applies to the statement, describing why you
chose the answer you did and cite an experiment or principle of Physics which
supports` your claim.
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Two identical solenoids are stacked one on top of the other with a
straight iron rod filling the cores. The bottom solenoid is
connected to a power supply and driving a current
counterclockwise around the solenoid, as seen looking down
from above.
[1] When the voltage from the power supply is increasing, the
induces current in the top solenoid flows counterclockwise.
[2] When the current in the lower solenoid is constant, the current in the upper solenoid is equal
and opposite to it.
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Coils A and B are both flat, circular coils.
[3] If coil A has 5 turns and an area of 15cm2
and coil B has 15 turns and an area of 5cm2
, they
will have the same inductance.
[4] If the two coils are rotated about an axis in the plane of the coils and they are in the same
uniform magnetic field, coil B must rotate faster to induce the same potential as coil A because
of the smaller flux through the smaller area.
[5] An electric potential will be generated in a coil placed in a magnetic field. The potential will
be greater if the coil is rotated or its area is changed.
[1] In a capacitor in an AC circuit, the electric field leads the current.
[2] The impedance of a capacitor increases with frequency.
[3] In an LR circuit with a switch, the current through the inductor when hte switch has
been closed for a long time is zero.
[4] The voltage across a capacitor in a DC circuit approaches its final value exponentially.
[5] To make a high pass filter, use an RC circuit with the output voltage measured across
the capacitor.
[6] In an RC circuit, the electric and magnetic fields reach their maximum values at the
same time.
[7] In an ideal transformer (no energy loss), the side with more turns gives a higher
voltage and larger current than the side with fewer turns.
[8] The inductance of a coil depends on the number and size of the coils and the material
in the wire.
[9] The capacitance of a capacitor is decreased by placing a material with a higher
dielectric constant between the plates.
[10] Like resistors, inductors in series and capacitors in series add, while inductors and
capacitors in parallel combine as the reciprocals.
[11] Once the initial phasors for an AC circuit are plotted, they each rotate at different
rates as time progresses.
Explanation / Answer
1>true
2>no,the current in upper solenid is zero
3>not always true because inductance depends on radius of wire and also L~N^2
4>not always true because voltage induced also depends on no. of turns
5>true because changing the area and rotating the coil changes the magnetic flux through the coil and so the voltage induced is increased