Worksheet rev - chapter 4A completed
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Worksheet – Chapter 4A
1.
List the 5 laws of electrostatics.
1.Repulsion-Attraction: This is a primary
precept
of electrostatics which states that like expenses repel every
different
and contrary
expenses
entice
every
different
. This conduct
is a essential component
of the interplay
among
electric powered
expenses
.
2. Inverse Square Law: This precept
is maximum
famously implemented
in Coulomb`s Law, which states that the pressure
among
factor
expenses
is immediately
proportional to the manufactured from
the magnitudes of the expenses
and inversely proportional to the rectangular
of the gap
among
them.. 3. Distribution: In electrostatics, this time period
refers to how price
is sent
on a conductor. When a conductor is charged in electrostatic equilibrium, the extra
price
is living
totally
at the
conductor's surface. Moreover, the price
tends to
be extra densely allotted
in regions
of excessive
curvature (sharp factors
or edges) than in flat regions
. 4. Concentration: This time period
is associated with
the distribution of price
and refers back to the
density of price
in a given area. As mentioned, the awareness
of price
is better
at factors
of sharp curvature. This is due to the fact
the electrical
subject
is more potent
at sharp factors
, and the sphere
traces
are nearer
together, indicating a better
awareness
of price
.
5.Movement: In the context of electrostatics, motion
typically
refers back to the
movement
of expenses
. In conductors, expenses
are loose
to transport
till
they attain
an equilibrium state. In insulators, expenses
are normally
now no longer
loose
to transport
. However, while
a capacity distinction
is implemented
, expenses
can flow
thru
a conductor, ensuing
in an electric powered current. In electrostatics, we usually
observe
expenses
at relaxation
and the forces and fields round
them, instead of
the motion
of expenses
that's
the focal point
of electrodynamics.
2.
Why are certain materials (conductors) able to conduct electricity?
Electrons withinside the
outermost shells are fantastically
loose
and could
simply
circulate
from one to another.
3.
Why is wood a good insulator?
Wood is taken into consideration
a very good
insulator normally
because of
its composition and shape
. It consists
of cellulose fibers, which can be
terrible
conductors of warmth
and electricity. These fibers incorporate
many air wallet
, which restrict
the cap potential
of warmth
to switch
thru
the timber
. Air itself is a superb
insulator, and those
wallet
of air inside the
timber
`s shape
beautify
its insulating properties. Additionally, the natural compounds in timber
do now no longer
have unfastened
electrons that could
circulate easily, that's
important
for the conduction of electricity. This loss of
unfastened
electrons makes timber
a terrible
conductor of electricity, thereby a very good
insulator
.
4.
Define electric potential.
a.
What is the unit used to measure it? The unit used to measure electric potential is the volt (V).
Electric capability
is a degree
of the capability
strength
according to
unit fee
at a factor
in an electric powered
field. The unit of electrical
capability
is the volt, that's
described
as one joule according to coulomb. In different
words, it represents the quantity
of labor
had to
flow
a fee
of 1 coulomb thru
an electric powered
capability
distinction
of 1
volt.
b.
What electric potential do we use to produce x-rays?
The electric potential used to produce x-rays usually
stages
from tens to loads
of kilovolts (kV). : X-ray machines perform
via way of means of
accelerating electrons and colliding them with a metallic
goal
to provide
x-rays. The electric powered
capability required to provide
x-rays is pretty
excessive
due to the fact
the electrons want
to be
multiplied
to excessive
speeds to have sufficient
strength
after they
collide with the goal
. This strength
is then transformed
into x-rays. The specific
capability
wished relies upon
at the
particular
software
and the preferred
strength
of the x-rays. Medical x-ray machines, for example, frequently
perform
withinside the
variety
of 30 to one hundred fifty
kV, at the same time as
commercial
machines can also additionally
use better
potentials.
5.
What is electrical current? What unit is used to measure it?
The unit used to measure electrical current is the ampere (A), which is one of the seven base units in the International System of Units (SI). One ampere is defined as the flow of one coulomb of charge per second. In equations and calculations, current is often represented by the symbol 'I'.
6.
What does electrical resistance mean? What unit is used to measure it?
Electrical resistance is a measure of the opposition to the flow of electric current through a conductor. It is
a property of materials that reduces the flow of electrons, and it can vary depending on the material's composition, temperature, and physical dimensions. The unit used to measure electrical resistance is the ohms.
7.
What is the difference between AC and DC electricity?
The difference between AC (Alternating Current) and DC (Direct Current) electricity lies in the direction in which the electrons flow. In DC electricity, the electrons flow in a single, constant direction. This type of current is typically produced by sources such as batteries, where the flow of electrons goes from the negative to the positive terminal. So the primary difference is that AC electricity involves a current that changes direction periodically, while DC electricity involves a current that flows in a single, constant direction. AC is used for power distribution in
grids, while DC is commonly used in electronic devices and power storage.
8.
What is the purpose for each of the following electrical devices?
a.
Switch
(A switch is a device that interrupts the flow of electricity in a circuit. It has the ability to turn a circuit on
and off, as well as divert current from one conductor to another. The basic function of a switch is to control the flow of electrical current in a circuit, allowing devices to be securely turned on or off.)
b.
Transformer
(A transformer is a device that transfers electrical energy between two or more circuits via electromagnetic induction. Its primary function is to increase (step up) or decrease (step down) the voltage in an alternating current (AC) electrical circuit while maintaining the frequency constant. This is required for efficient power transmission over long distances and giving adequate voltage levels to diverse devices.)
c.
Rheostat
(A rheostat is a variable resistor that controls the current flowing through a circuit. Its primary function is to change the strength of current by varying the resistance, which can control things like the brightness of a light or the speed of a motor. It is commonly employed in applications that require the resistance of a circuit to be varied without interruption.)
d.
Diode
A diode is a semiconductor device that allows current to flow in a single direction alone. It contains two terminals, an anode and a cathode, and is commonly used for rectification (converting alternating current to direct current), voltage regulation, signal demodulation, and circuit protection by stopping reverse current.
e.
Battery
(A battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. The main purpose of a battery is to provide a portable source of electrical power to operate devices that are not connected to the grid, or as a backup power source in case of power failures.)
9.
Why is a magnetic material “magnetic”?
The key to a material being "magnetic" is the alignment of electron spins and the ability of the material to maintain that alignment to some extent, which results in a net magnetic field For this reason, magnetic materials include iron, which can maintain this alignment in the absence of an external magnetic field. A substance is deemed "magnetic" when a sizable portion of its electron spins are
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aligned in the same direction, producing a net magnetic moment. In ferromagnetic materials, this alignment is intrinsic; in paramagnetic materials, it is produced by an external magnetic field.
10.
Define electromagnetic induction.
Electromagnetic induction is the process of generating an electromotive force (EMF) across an electrical conductor due to a changing magnetic field.
11.
Explain how generators and motors use electromagnetic induction.
In order to transform mechanical energy into electrical energy and induce an electric current, generators
use electromagnetic induction, which involves rotating a coil inside a magnetic field. Motors use electromagnetic induction as well, but in reverse. By running a current through a coil inside of a magnetic field, they produce force and motion by converting electrical energy into mechanical energy.
12.
Why is an AC power source required for a transformer to work?
An AC power source is required for a transformer to work because it provides the varying magnetic field needed for electromagnetic induction to occur, which is the fundamental principle on which transformers operate.
13.
What is the advantage of closed core and shell type transformer configurations?
When compared to alternative transformer designs, closed core and shell-type transformer topologies offer better efficiency, dependability, and performance. They are ideal for a variety of electrical power distribution and transmission applications due to their sturdy, compact design, lower losses, and improved cooling capabilities.
14.
In a step down transformer:
a.
How is voltage and current affected?
A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. A step-down transformer reduces the voltage from the primary to the secondary coil while increasing the current. This is based on the principle of conservation of energy and the transformer equations which relate the primary and secondary voltages and currents to the number of turns on the primary (Np) and secondary (Ns).
n a step-down transformer, the voltage is decreased, and the current is increased on the secondary side compared to the primary side.
b.
What happens as the number of coils are decreased on the secondary side?
A transformer's turns ratio indicates how much the voltage is impacted by the number of turns in its coils. With the assumption that the number of turns on the primary side stays constant, the turns ratio (Np/Ns) increases if the number of coils (turns) on the secondary side is reduced. This implies that in
comparison to the primary voltage, the secondary side's voltage will drop even more. This is so because the number of turns in the secondary coil directly relates to the voltage that is induced in it. Consequently, the voltage is further decreased with fewer rotations on the secondary, increasing the current even further, as stated by the idea of energy conservation, which assumes steady power and minimal losses. As the number of secondary side coils decreases, the secondary side voltage drops even more, and current rises as long as power stays constant and losses are minimal.
15.
Why are diodes or rectifiers necessary in an x-ray circuit?
Diodes or rectifiers are necessary in an x-ray circuit to convert alternating current (AC) into direct current (DC), ensuring a steady and unidirectional flow of electrons within the x-ray tube for the consistent production of x-rays and to prevent damage to the tube.
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