Everything else Flashcards
branch
any portion of a circuit that can be simplified as having two terminals
very useful for controlling the voltage in another circuit.
Potentiometers
Unit of capacitance
the farad
The total capacitance of two capacitors connected in series is less than that of either capacitor alone
True
If a conductor has a capacitance of one farad, a transfer of one coulomb of charge to the conductor will increase its potential by one volt.
True
The capacitance of a given capacitor will be higher if the separation of the plates is reduced without changing the dielectric.
True
Insertion of a dielectric between the plates of a capacitor decreases the voltage across it and hence reduces the capacitance.
False
If the charge on a capacitor is doubled, the potential energy will be quadrupled.
True
For capacitors connected in parallel, the voltage across each capacitor is the same as that across the source.
True
The amount of charge that can be placed on a conductor does not depend on
its potential
The capacitance of a capacitor increases with a decrease in
plate separation
The total voltage is the sum of the voltages across each capacitor.
capacitors in series
have the ability to store a charge
Capacitors
Capacitance is directly proportional to
charge
is a measure of how easy it is to establish electric flux in a material
Permittivity
Capacitors in series are treated the same as
resistors in parallel
The dielectric constant may also be referred to as the relative
of a material
The total capacitance of a number of capacitors connected in series is_________the capacitance of any capacitor taken individually
less than
The_____________for a material is the ratio of the capacitance with that material between the plates to the capacitance for a vacuum between the plates.
dielectric constant
A group of capacitors connected directly to the same source of potential difference so that the available charge is shared are said to be connected in
parallel
Current in a capacitor exists only while capacitor voltage
is changing
A capacitor stores charge Q at a potential difference ΔV. If the voltage applied by a battery to the capacitor is doubled to 2ΔV
the capacitance remains the same and the charge doubles
Two capacitors are identical. They can be connected in series or in parallel. If you want the smallest equivalent capacitance for the combination, you should connect them in
series
Consider two identical capacitors. Each capacitor is charged to a voltage of 10 V. If you want the largest combined potential difference across the combination, you should connect them in
series
You have three capacitors and a battery. In which of the following combinations of the three capacitors will the maximum possible energy be stored when the combination is attached to the battery?
parallel
refers to the force that acts between magnets and magnetic materials
Magnetism
a magnetic field is a
force field
The lines of force between the north pole and south pole of a permanent magnet or an electromagnet.
Magnetic flux
The SI unit of magnetic flux, which represents
108lines
Weber (Wb)
The measure of ease with which a magnetic field can be established in a material
Permeability
The opposition to the establishment of a magnetic field in a material
Reluctance
Faraday’s law
A law stating that the voltage induced across a coil of wire equals the number of turns in the coil times the rate of change of the magnetic flux
A unit of flux density that is the same as a Wb/m2 is the
tesla
The Weber is a unit of what?
Magnetic Flux
The cause of magnetic flux is
magnetomotive force
The measurement unit for permeability is
weber/ampere-turn-meter
The measurement unit for relative permeability is
dimensionless
The property of a magnetic material to behave as if it had a memory is called
hysteresis
In a series capacitor circuit, the total capacitance is
Smaller than the smallest individual capacitor value
The control voltage for a relay is applied to the
coil
When the current through a coil changes, the induced voltage across the coil will
oppose the change in the current that caused it
Magnetic Lines of Force, go from North to South.
And never
cross over each other
Loads are commonly connected in:
In parallel so that they operate independently
Michael Faraday & Joseph Lenz
The two people mostly responsible for our ideas concerning inductance and induced voltages
Voltage is induced in a circuit whenever the flux linking (i.e., passing through) the circuit is changing and that the magnitude of the voltage is proportional to the rate of change of the flux.
Faraday’s Law
The greater the number of flux lines cut per unit time or the stronger the magnetic field strength
the greater will be the induced voltage across the conductor
an induced current is always such a direction to oppose the motion or change causing it.
Lenz’s law
Reluctance is the same to a magnetic circuit as _________is to an electric circuit
Resistance
L is called the self-inductance of the coil, and in the SI system its unit is the
henry
capacitors in series are treated the same as
resistors in parallel
The law that states that the induced effect is such that it opposes the cause that produced it is:
Lenz’s Law
Increasing levels of inductance can be obtained by placing inductors
in series
The inductance of a multi-turn coil depends on
geometry of coil
The unit of inductance (henry) is equivalent to
Wb/A
Using inductance to shift from measuring flux changes to measuring current
changes simplifies the use of whose law?
Faraday
The permittivity constant is generally denoted by
ε
The summation of currents entering a node is equal to the summation of currents leaving the node
Kirchhoff’s Current Law
