RAD 111 Lecture 2
One kilovolt is equal to ____________ V. 1,000 1/100 1/1,000 1/10
1,000
How much power was used in a mobile radiographic unit with 220 V and 0.8 A? 275 W 176 W 0.0036
176 W Electric power is the rate of energy consumption in an electrical circuit and is measured in units of watts. P is the electric power in watt (W) V is the voltage in volts (V) I is the current in amps (A) To calculate power rating use the equation: P = IV; P (power) = I (amps) times V (volts) P = 0.8 A multiplied by 220 volts (V) = 176 watts
Electric insulators inhibit the movement of electric charge permit the movement of electric charge store electric charge change electric charges from positive to negative
inhibit the movement of electric charge An electrical insulator is a material whose internal electric charges do not flow freely, and therefore make it very hard to conduct an electric current electric. Insulators are resistant to the free flow of electrons because the electrons in insulating materials are tightly bound. Glass, wood, rubber, ceramics, and many plastics are good insulators.
Alternating current is required for any device that operates on the basis of electromagnetic induction. True False
True Electromagnetic induction is the production of a current in a conductor by a changing magnetic field that is located near the conductor. AC current produces the changing magnetic field required for electromagnetic induction.
When a charged particle is put in motion an electric dipole has been ionized a magnetic field is created it allows positive charges in a conductor to move, also gamma radiation results
a magnetic field is created Magnetism is caused by electrons moving inside atoms and creating magnetic fields all around them. The spin of an electron combined with it electric charge, results in a magnetic dipole moment and creates a magnetic field. If the electron spin of an atom's electrons are align to form magnetic domains in certain materials such as iron, the iron will be magnetized.
Which of the following are classified as diamagnetic materials? copper and beryllium copper, beryllium, and iron copper and iron beryllium and iron
copper and beryllium Diamagnetic materials have a very weak and negative susceptibility to magnetic fields. Diamagnetic materials include beryllium, bismuth, copper, gold, silver, and lead.
Amperage is used to define coulomb of charge passing a given point in one second resistance offered by the flow of electricity electromotive force impressed on the conductor direction of flow of electrons through a conductor
coulomb of charge passing a given point in one second Amperage is the strength of a current of electricity. It is a measure of the amount of electrons moving in a circuit and is express in amps or amperes (A).
A coiled helix carrying an electric current is known as a solenoid generator transformer rectifier
solenoid Commutator A commutator is a series of bars or segments connected to the armature coils of a generator or motor so that rotation of the armature will in conjunction with fixed brushes result in unidirectional current, or direct current, output in the case of a generator and in the reversal of the current into the coils in the case of a motor Generator A generator is a mechanical device that generates electricity. The electrical energy produced by a generator is either direct current (DC) or alternating current (AC). Rectifier A rectifier is a device that converts alternating current (AC) to direct current (DC). AC repeatedly reverses direction and DC flows in one direction only. Solenoid A coiled helix (coil of wire) that carries current (flow of electrons) is called a solenoid. The solenoid acts like a magnet when a current passes through it.
The laws of magnetism include all of the following except like poles repel stronger magnets have larger poles unlike poles attract force between magnets decreases with the square of the distance
stronger magnets have larger poles The three (3) basic laws of magnetism are: Like poles repel, unlike poles attract. Every magnet has a north pole and a south pole. The magnetic force between two magnetic fields is directly proportional to the product of their magnitude and inversely proportional to the square of the distance between them.
A ferromagnetic material is not influenced at all weakly influenced by a magnetic field strongly influenced by a magnetic field repelled by a magnetic field
strongly influenced by a magnetic field Ferromagnetic materials have a large, positive susceptibility to an external magnetic field and exhibit a strong attraction to magnetic fields. When a ferromagnetic material is magnetized the atomic dipoles within the material align parallel to each other to create areas of strong magnetization within the material called magnetic domains. This alignment tends to persist even after the magnetic field is removed. When a ferromagnetic material is not magnetized it still has domains, but the domains have random magnetization directions that cancel each other out.
The unit of electrical power is the volt ohm watt ampere
watt Ampere (A) The ampere is a unit that expresses the rate of flow of an electric current. Ampere is defined as electric current flowing at the rate of one coulomb per second. Ohm ( Ω) Ohm is A unit of electrical resistance defined as the resistance of a circuit with a voltage of one volt and a current flow of one ampere. Volt (V) Volt is a unit of electrical potential. A volt is the electrical potential needed to produce one ampere of current with a resistance of one ohm. Electrical potential is the force required to move a charge through a circuit. Watt (W) Watt is a unit of power, defined as one joule per second. Wattage is calculated as Voltage x Amperage.
Which of the following situations would serve to increase the resistance of a wire? reducing the temperature reducing the distance doubling the length doubling the diameter
doubling the length Resistance is a force, which opposes the flow of an electric current around a circuit. The resistance in a wire can be increased by: Increasing the length. (Resistance in a wire is directly proportional to the length provided the cross sectional area remains constant, so the longer the wire, the greater the resistance). Increasing the temperature. (At a constant temperature, resistance in a wire is directly proportional. (Generally metals offer more electrical resistance if temperature is increased. On the other hand the resistance offered by a non - metallic substance normally decreases with increase of temperature). Decreasing the cross sectional area. (Resistance in a wire is inversely proportional to the cross sectional area; the resistance of a thin wire is greater than the resistance of a thick wire). Using an insulator material: (Some material resist the flow of electrons and others allow electrons to flow freely. Insulators are materials with tightly bound atoms that do not permit electrons to flow easily, e.g. opposes the flow of electrons. Examples of insulator materials are glass, plastic, rubber, air, and wood. Conductors are materials with loosely bound outer shell electrons, or free electrons, which permits electrons to flow easily. It can be said that insulators have a very high resistance and conductors have a low resistance). Using a coiled conductor: (When a conductors has bends or curves, the amount of resistance increases. There is an inverse relationship between the straightness of a conductor and the amount of resistance present within the conductor).
An electric motor converts mechanical energy to electrical energy electrical energy to chemical energy chemical energy to electrical energy electrical energy to mechanical energy
electrical energy to mechanical energy An electric motor is a device that converts electrical energy to mechanical energy. Electric motors can be divided into two types alternating current (AC) motors and direct current (DC) motors. Both of these motors produce mechanical energy but the difference lies in the current supply. DC motors are driven by continuous electric current which flows only in one direction, while AC motors work upon a current that changes, or alternates, its direction repeatedly after every cycle.
A solenoid with an iron core in its center is called a/an electromagnet motor lodestone generator
electromagnet Electromagnetic A solenoid (current-carrying coil of wire) wrapped around an iron core is an electromagnetic. An electromagnet is a non-permanent magnet in which the magnetic field is produced by the flow of an electric current through the coil. Unlike a permanent magnet, the strength of an electromagnet can easily be changed by changing the amount of electric current that flows through it. Electromagnet converts electrical energy into mechanical energy. It is used in many electromechanical devices such as circuit breakers, motors, relays, etc. Generator A generator is an electromagnetic device that transforms mechanical energy to electrical energy. Lodestone Lodestone is the strongest naturally occurring magnet, which is a form of the mineral magnetite. It can attract small objects, like paper clips and staples. Motor A motor is an electromagnetic device that transforms electrical energy to mechanical energy.
Mechanical energy can be converted into electrical energy by a battery motor capacitor generator
generator Battery A battery is a device containing an electric cell or a series of electric cells storing chemical energy that can be converted into electrical power, usually in the form of direct current. Capacitor A capacitor is a device that is used to temporarily store electric charge. Generator A generator is an electromagnetic device that transforms mechanical energy to electrical energy. Motor A motor is an electromagnetic device that transforms electrical energy to mechanical energy.
What types of material would be the best insulator? tap water copper glass silver
glass An electrical insulator is a material that resists electric current, and will not allow it to flow easily. Glass is a good electrical insulator because the electrons in the glass are tightly bound to the atoms and do not transfer easily, thus keeping electricity from moving through the glass. Metals such as copper and silver make excellent electrical conductors. An electrical conductor is a material that offers very little resistance to electric current, allowing it to flow freely and easily. Tap water is also a good conductor due to the minerals (i.e., chlorine, nitrates, leads, and others) in it but distilled water or pure water is not a good conductor because it is just hydrogen and oxygen, which are poor conductors.
According to electromagnetic induction principles, which of the following situation will serve to increase the amount of voltage produced? slowing the motion of the coil increasing the number of loops in the wire stopping the motion of the magnet changing the motion of the magnet from 90 degrees to parallel
increasing the number of loops in the wire Electromagnetic induction is the creation of an electrical voltage - or potential difference - across a conductor within a changing magnetic field. The induced voltage can be increased by: Increasing the number of turns in the conducting coil. Increasing the strength of the magnet field. Increasing the speed of motion between the lines of force and the conductor Aligning the conducting coil 90 degrees to the magnetic field lines
What type of motor drives the rotating anode in the x-ray tube? direct current motor alternating motor induction motor synchronous motor
induction motor The rotating anode in the x-ray tube is turned using an AC induction motor that operates through the process of electromagnetic induction. The AC induction motor consists of a rotor and several stators (electromagnets). The anode assembly is attached to the rotor that is contained within the evacuated glass envelope of the x-ray tube. The stator coils (which produce the changing magnetic field) are fixed around the outside of the envelope and encircle the area of the rotor. The changing magnetic field produced by the stators penetrates the glass envelope and induces a current to flow in the rotor. The induced current in the rotor interacts with the changing magnetic field produced by the stators, forcing the rotor to spin.
The core of an electromagnet should be made of tungsten copper iron silver
iron An electromagnetic is a temporary magnet made by coiling wire around a ferromagnetic material such as a soft iron; when current flows in the coil the iron becomes a magnet having a north pole at one end and a south pole at the other. Soft iron is most commonly used for the core material because it can easily be magnetized and demagnetized, which permits the electromagnet to be turn on and off. It also concentrates the magnetic flux and makes a more powerful magnet.
Which of these material is ferromagnetic? glass plastic wood iron
iron There are 4 major magnetic classifications of materials. Ferromagnetic materials: Ferromagnetic materials are strongly attracted to a magnetic field. Examples of ferromagnetic materials include cobalt, iron, nickel, and alnico (an aluminum-nickel-cobalt alloy). Paramagnetic materials: Paramagnetic materials have a weak attraction to magnetic fields and the material does not retain any magnetic properties when the external magnetic force is removed. Examples of paramagnetic materials include gadolinium, magnesium, and molybdenum. Diamagnetic materials: Diamagnetic materials are weakly repelled by magnetic fields. Examples of diamagnetic material include copper, gold and silver. Nonmagnetic materials: Nonmagnetic materials are not affected by magnetic fields and cannot be magnetized. Examples of nonmagnetic materials include wood, rubber, plastics, glass, and leather.
A group of atoms with their dipoles lined up in the same direction is termed magnetic flux magnetic field magnetic induction magnetic domain
magnetic domain Magnetic domain A magnetic domain simply means that the individual magnetic moments of the electrons are aligned parallel with each other, all pointing in the same direction. It is what makes a ferromagnetic material magnetic. Magnetic field A magnetic field is an invisible field that exerts a magnetic force on substances that are sensitive to magnetism. A magnetic field can be created with moving charges, such as a current-carrying wire. A magnetic field can also be created by the spin magnetic dipole moment, and by the orbital magnetic dipole moment of an electron within an atom. Magnetic flux Magnetic flux is used to describe the total amount of magnetic field in a given region. The term flux was chosen because the power of a magnet seems to "flow" out of the magnet at one pole and return at the other pole in a circulating pattern. Magnetic induction Magnetic induction is the process by which a substance, such as iron or steel, becomes magnetized by a magnetic field. The induced magnetism is produced by the force of the field radiating from the poles of a magnet.
Voltage can be induced in a wire by rubbing magnets together placing the south pole of a magnet near the north pole of another magnet connecting it to a galvanometer moving a magnet near the wire
moving a magnet near the wire A magnetic field of changing intensity perpendicular to a wire will induce a voltage along the length of that wire. The amount of voltage induced depends on the rate of change of the magnetic field flux and the number of turns of wire (if coiled) exposed to the change in flux. The voltage is induced, and a current is generated, only when the magnet and the wire (coil) move relative to each other. This is because a conductor must cut across magnetic field lines for a voltage to be induced. This phenomenon is known as electromagnetic induction. Electromagnetic induction is the production of electricity (electric current) by a changing magnetic field and a stationary conductor or moving the conductor relative to the stationary magnetic field.
Faraday's law states that electrical current will flow through a conductor when it is placed in a stationary magnetic field moving magnetic field
moving magnetic field According to Faraday's law, electrical current is created in conductor (wire) if it is placed in the changing magnetic field. It also states that any change in the flow of an electric current in a conductor (wire) will create magnetic field around that conductor.
In an electric circuit, electrons move from negative to positive positive to negative neutral to negative neutral to positive
negative to positive Electron flow is the basis of electrical current in a circuit. Electrons have a negative charge and therefore they flow from the negative terminal towards the positive terminal in a circuit. However before the true nature of electricity was known scientists assumed that current was the result of the movement of positively charged particles and therefore that current flowed from the positive to the negative terminal. This (incorrect) convention is still used today and is called conventional current flow.
The field lines of a magnet flow parallel to the magnet either parallel or perpendicular to the magnetic perpendicular to the magnetic
perpendicular to the magnetic Magnetism is the result of electric charge motion. As soon as an electric charge moves, it creates a magnetic effect perpendicular to its direction of motion.
An excessive amount of electrons at one end of a conductor and a deficiency at the other end is known as potential difference resistance impedance quantum
potential difference Impedance Impedance is all of the effects on a circuit that oppose the flow of an AC current consisting of inductance, capacitance, and resistance. It can be quantified in the units of ohms. Potential Difference (PD) An excessive amount of charges (i.e., electrons) at one end of a conductor and a deficiency at the other end is called potential difference (PD) or voltage. Potential difference is the voltage difference between any two points in a circuit and it is the difference between these two points that makes the current flow. The unit of potential difference generated between two points is called the volt (V). Quantum Quantum is one of the very small discrete packets into which many forms of energy are subdivided. Resistance Resistance is the opposing force that hinders the flow of electric current. The unit of measure for resistance is the ohm (). It can also be defined as the characteristic of materials to oppose the flow of electricity in an electric circuit.
In an induction motor, which components are primarily responsible for making the anode spin? stators and rotor brushes and split rings electromagnets and commutator ring capacitor and commutator ring
stators and rotor The induction motor, which converts electrical energy to mechanical energy, causes the rotating anode to spin in the x-ray tube. The induction motor consists of a rotor located inside the glass envelope of the x-ray tube and a series of stators (electromagnets) located outside the glass envelope surrounding the area of the rotor. The stators produce a changing magnetic field that induces a current to flow in the rotor. The induced current in the rotor interacts with the changing magnetic field from the stators, forcing the rotor to spin.
The force needed to pass a current of one ampere through a resistance of 1 ohm is the definition for the watt coulomb volt ampere
volt Ampere Ampere is the standard unit of electric current. The current produced by a pressure of one volt in a circuit having a resistance of one ohm. Coulomb The SI derived unit used to measure electric charge. One coulomb is equal to the quantity of charge that passes through a cross-section of a conductor in one second, given a current of one ampere. Volt The volt is the unit of electromotive force (EMF) that causes current to flow. One volt causes a current of one amp through a resistance of one ohm. Watt The watt is the SI unit used to measure power, equal to one joule per second. In electricity, a watt is equal to current (in amperes) multiplied by voltage (in volts).
The unit of electrical potential is the volt watt coulomb ampere
volt Ampere (A) The ampere is a unit that expresses the rate of flow of an electric current. Ampere is defined as electric current flowing at the rate of one coulomb per second. Ohm ( Ω) Ohm is A unit of electrical resistance defined as the resistance of a circuit with a voltage of one volt and a current flow of one ampere. Volt (V) Volt is a unit of electrical potential. A volt is the electrical potential needed to produce one ampere of current with a resistance of one ohm. Electrical potential is the force required to move a charge through a circuit. Watt (W) Watt is a unit of power, defined as one joule per second. Wattage is calculated as Voltage x Amperage.
All of the following materials are ferromagnetic except wood nickel iron cobalt
wood Ferromagnetic materials are strongly magnetized even in the absence of external magnetic field. Examples of ferromagnetic materials are: Iron, nickel, cobalt, alnico (an aluminum-nickel-cobalt alloy), and gadolinium and their alloys.
The equation, V = IR, is used to express magnetic flux Ohm's law power loss conservation of energy law
Ohm's law The equation V = IR is used to express Ohm's Law which describes the relationship between voltage, current, and resistance in a circuit. Ohm's Law states that for a metal conductor at constant temperature, the current flowing through it is directly proportional to the voltage across it. The equation V = IR tells us that the voltage (V) across the total circuit or any part of a circuit is equal to the current (I) flowing through the conductor multiplied by the resistance (R) of the conductor.
The unit of electric current is the ampere ohm watt volt
ampere Ampere (A) The ampere, or amps, is the unit expressing the rate of flow of an electric current. One ampere is the current produced by a difference in potential of one volt across a resistance of one ohm. Ohm (Ω) The ohm is a unit of electrical resistance defined as the resistance of a circuit with a voltage of one volt and a current flow of one ampere. Volt (V) The volt is a unit of voltage (electromotive force or electrical potential). It is the electrical potential needed to produce one ampere of current with a resistance of one ohm Watt (W) The watt is a unit of power equal to the rate of work represented by a current of one ampere under a pressure of one volt.
A changing magnetic field produces insulation an electric field electromagnetic radiation sound waves
an electric field A changing magnetic field produces an electric field. This electric field will cause electrons to flow in a conductor. It is important to note that in this situation the magnetic field must be changing; a steady magnetic field relative to a conductor does not induce an electric current. This phenomenon is referred to as electromagnetic induction. Electromagnetic induction is a process in which a conductor is placed in a changing magnetic field (or a conductor moving through a stationary magnetic field) causes the production of a voltage across the conductor, which, in turn, causes an electrical current (flow of electrons). There must be a relative motion between the magnetic and the conductor.
Two magnets with the same poles facing each other will experience a force times the distance be attracted be repelled experience no force
be repelled Magnetism is a force that is created when objects are attracted or repelled by one another. A magnetic field is the area around a magnet. The larger the magnet and the closer an object is to the magnet, the greater the force of the magnetic field. A magnet has two ends called poles, one of which is called a north pole or north-seeking pole, while the other is called a south pole or south-seeking pole. The magnetic strength of a magnetic is strongest at these poles. The north pole of one magnet attracts the south pole of a second magnet, while the north pole of one magnet repels the other magnet's north pole. In other words, like poles repel, unlike poles attract.
What is the resistance in a circuit with 12,000 V and 65 A? 78 ohms 0.19 ohms 185 ohms 0.005 ohms
185 ohms Ohm's Law describes mathematically how voltage, current, and resistance in a circuit are related. By knowing any two values of the voltage, current or resistance quantities Ohm's Law can be used to find the third missing value. Ohm's Law can be states as three equations: V = IR; I= V/R; R = V/I The letters E or V symbolize voltage, measured in volts (V) The letter I symbolize current, measured in amperes, or amps (I) The letter R symbolize resistance, measured in ohms (Ω) To calculate current use the equation: R = V/I R (resistance) = V (volts)I / (amps) R = 78 V divided by 20 amps = 3.9 ohms (Ω)
A current through a 5 ohm resistor connected to a 220 volt outlet is 44 amperes 220 volts 5 ohms 1.100 amperes
44 amperes Ohm's Law describes mathematically how voltage, current, and resistance in a circuit are related. By knowing any two values of the voltage, current or resistance quantities Ohm's Law can be used to find the third missing value. Ohm's Law can be states as three equations: V = IR I= V/R R = V/I The letters E or V symbolize voltage, measured in volts (V) The letter I symbolize current, measured in amperes, or amps (I) The letter R symbolize resistance, measured in ohms (Ω) To calculate current use the equation: I = V/R; I (amps) = V (volts) x R (resistance)I = 220 V divided by 5 ohms = 44 amperes (I)
A simple DC generator is similar to an AC generator except that a DC generator is constructed with brushes slip rings commutator an armature
commutator The main difference between a DC generator and an AC generator lies in the manner in which the rotating coil is connected to the external circuit. In an AC generator, both ends of the coil are connected to separate slip-rings which co-rotate with the coil, and are connected to the external circuit via wire brushes. This means each end of the armature is always connected to the same end of the external circuit. The current in the external circuit changes direction every time the current in the armature changes direction. Thus the external circuit carries alternating current.In a DC generator, the two ends of the coil are attached to different halves of a single split-ring which co-rotates with the coil. The split-ring is connected to the external circuit by means of metal brushes. This combination of a rotating split-ring and stationary metal brushes is called a commutator. The commutator periodically switches the direction of the current flow from the rotor to the external circuitry to generate in a current that does not change direction (DC).
The four types of electrical materials are conductors, insulators, semiconductors, and superconductors conductors, inflectors, semiconductors, and superconductors convection, insulators, semiconductors, and supercollectors conductors, ferromagnetic, electromagnetic, and insulators
conductors, insulators, semiconductors, and superconductors The four types of electrical materials are: Conductors: A conductor is a material that allows free movement of electrons and therefore allows easy flow of electricity. In good conductors, the valence electrons (the electrons that are in the last energy level of the atom) move freely from atom to atom, which facilitates the flow of electrical current. The best conductors are usually metals. Silver, copper, and gold are good conductors. Insulators: An insulator is a material that blocks or retards the flow of electrons, (e.g., electric current), or heat. An insulator is a poor conductor because it has a high resistance to the flow of electrons. Electrical insulators include rubber, plastic, porcelain, and mica. Semiconductors: Semiconductors are materials that have electrical conductivity greater than insulators but less than good conductors. Such materials can be treated chemically to allow transmission and control of an electric current (e.g., flow of electrons). Semiconductors are made of germanium, silicon, gray (crystalline) tin, selenium, tellurium, and boron. Germanium and silicon are two of the best-known semiconductors. They are used extensively in devices such as rectifiers and transistors. Superconductors: A superconductor an element or metallic alloy which, when cooled to near absolute zero, has no electrical resistance. In principle, superconductors can allow electrical current to flow without any energy loss. Materials that will form superconductors come in two basic varieties, those which are metals (e.g., mercury, niobium, tin, lead) or alloys of metals and the newer variety that are ceramic-like materials. Superconductors are used to produce magnetic fields in magnetic resonance imaging units.
In order to maintain its superconductivity a superconductor must be heated cooled magnetized energized
cooled A superconductor is a material that has zero electrical resistance at certain temperatures; it is the perfect conductor. Superconductors have to be made very cold before they will enter the superconductive state with perfect conductivity. This perfect conductivity means that if you have a superconductor in a closed loop which carries current around the loop, it will continue to carry it forever without loss. The major use for superconductors is for high-powered magnets in magnetic resonance imaging machines and particle accelerators.
During the process of mutual induction current flows in only one direction current is transferred from one coil to another electrons flow is impeded a semiconductor becomes magnetized
current is transferred from one coil to another Mutual inductance is where the magnetic field generated by a coil of wire induces voltage in an adjacent coil of wire. This means that if two coils of wire are brought into close proximity with each other so the magnetic field from one links with the other, a voltage will be generated in the second coil as a result. Mutual inductance is the basic operating principal of the transformer, motors, generators and any other electrical component that interacts with another magnetic field.
According to Ohm's law increasing the resistance in a circuit results in a(an) increase in current increase in voltage decrease in current decrease in voltage
decrease in current Electrical current is affected by the voltage and resistance in a circuit. The relationship between voltage, current, and resistance is described by Ohm's law. This equation, I = V/R, tells us that the current, I, flowing through a circuit is directly proportional to the voltage, V, and inversely proportional to the resistance, R. In other words, if we increase the voltage, then the current will increase. But if resistance is increased (assuming voltage remains constant) then the current will decrease.
Which type of magnetic material is weakly repelled by other magnetic fields? nonmagnetic ferromagnetic paramagnetic diamagnetic
diamagnetic The magnetic behavior of materials can be classified by the 4 major groups: Diamagnetic materials Diagmagnetic materials weakly repel a strong magnet. Examples include copper, beryllium, bismuth, and lead. Ferromagnetic materials Ferromagnetic materials are strongly attracted to a magnetic force. Examples include iron, nickel, and cobalt. Paramagnetic materials Paramagnetic materials are weakly attracted to a magnet. Examples include aluminum and platinum. Nonmagnetic materials Nonmagnetic materials do not possess any magnetic and therefore do not react with magnetic fields. Examples include wood, glass, rubber, and plastics.
Which of the following is inversely proportional to the resistance in a circuit? length of the conductor temperature of the conductor diameter of the conductor magnetic field strength
diameter of the conductor The resistance in a circuit is an opposing force that hinders the flow of electric current (free electrons). There are five (5) main variables the impact the resistance in an electric circuit. Conduction material: Materials that serve as good conductors, allowing current to flow easily, includes metals such as iron, silver, gold, copper, and graphite. Materials considered to be good insulators than hinder the flow of current include glass, rubber, plastic, fiberglass, oil, and porcelain. Diameter of conductor: The larger the diameter (cross section) of the conductor, the easier it is for current to flow. There is an inverse relationship between the diameter of the conductor and the amount of resistance present within the conductor. For example a large diameter conductor has a low resistance and a small diameter conductor has a high resistance. Length of conductor: As the length of the conductor increases, more resistance occurs. There is a direct relationship between the length of the conductor and the amount of resistance present within the conductor. For example a long conductor has a high resistance and a short conductor has a low resistance. Straight-line conductor: There is less resistance with a conductor that lies in a straight line. When a conductor has bends or curves, the amount of resistance increases. There is an inverse relationship between the straightness of a conductor and the amount of resistance present within the conductor. For example a straight conductor has a lower resistance compared to a curved or coiled conductor, which has a higher resistance. Temperature of conductor: As the temperature of the conductor increases (heat), the amount of resistance increases. There is a direct relationship between conductor temperature and amount of resistance present within the conductor. For example as the temperature of a conductor increases, the resistance increases and as the temperature of a conductor decreases the resistance decreases.
What happens in a parallel circuit if one of four branches fails? circuit remains closed and electrons flow through the remaining branches Circuit becomes open, and electrons stop flowing electrons will continue to flow in the open circuit electrons will only move along the main line of the circuit
circuit remains closed and electrons flow through the remaining branches A parallel circuit has more than one path for current flow and the same voltage is applied across each branch of the circuit. If one branch is broken, current will continue flowing to the other branches and the devices on the different branches will keep working. Parallel circuits are useful if you want electrical devices to continue to work, even if one branch of the circuit has failed.
The units of magnetism are the volts and tesla tesla and gray gauss and coulomb tesla and gauss
tesla and gauss Coulomb The coulomb (C) is the standard unit of electric charge in the International System of Units (SI) defined as the quantity of electric charge transferred across a surface by 1 ampere in 1 second. Gauss Gauss is the centimeter-gram-second (cgs) unit of magnetic induction. Gray A gray (Gy) is the SI derived unit of absorbed dose and specific energy (energy per unit mass). Such energies are usually associated with ionizing radiation such as X-rays. It is defined as the absorption of one joule of energy in the form of ionizing radiation by one kilogram of tissue. Tesla Tesla is a unit of magnetic induction equal to one weber per square meter. Volt Volt (V) is the SI unit of electric potential or electromotive force equal to 1 watt per ampere or 1 joule per coulomb.
When a circuit has 110 V and 9 Ω, what is the amperage flowing through the circuit? 9.9 A 0.08 A 990 A 12.2 A
12.2 A Ohm's Law describes mathematically how voltage, current, and resistance in a circuit are related. By knowing any two values of the voltage, current or resistance quantities Ohm's Law can be used to find the third missing value. Ohm's Law can be states as three equations: V = IR; I= V/R; R = V/I The letters E or V symbolize voltage, measured in volts (V) The letter I symbolize current, measured in amperes, or amps (I) The letter R symbolize resistance, measured in ohms (Ω) To calculate current use the equation: I = V/R; I (amps) = V (volts) x R (resistance) I = 110 V divided by 9 ohms = 12.2 or 12 amperes (I)
What is the power rating of a lamp that carries 2 A at 120 V? 60 W 0.167 W 120 W 240 W
240 W Electric power is the rate of energy consumption in an electrical circuit and is measured in units of watts. P is the electric power in watt (W) V is the voltage in volts (V) I is the current in amps (A) To calculate power rating use the equation: P = IV: P (power) = I (amps) times V (volts) Power = 2 A multiplied by 120 volts (V) = 240 watts
A circuit has a potential difference of 78 V and a current of 20 A. What is the resistance in the circuit? 3.9 ohms 58 ohms 1,560 ohms 0.25 ohms
3.9 ohms Ohm's Law describes mathematically how voltage, current, and resistance in a circuit are related. By knowing any two values of the voltage, current or resistance quantities Ohm's Law can be used to find the third missing value. Ohm's Law can be states as three equations: V = IR; I= V/R; R = V/I The letters E or V symbolize voltage, measured in volts (V) The letter I symbolize current, measured in amperes, or amps (I) The letter R symbolize resistance, measured in ohms (Ω) To calculate current use the equation: R = V/I R (resistance) = V (volts)I / (amps) R = 78 V divided by 20 amps = 3.9 ohms (Ω)
If a current of 0.5 A flows through a conductor and has a resistance of 6 ohms, the voltage is 12 V 6.5 W 3 V 3 A
3V Ohm's Law describes mathematically how voltage, current, and resistance in a circuit are related. By knowing any two values of the voltage, current or resistance quantities Ohm's Law can be used to find the third missing value. Ohm's Law can be states as three equations: V = IR I= V/R R = V/I The letters E or V symbolize voltage, measured in volts (V) The letter I symbolize current, measured in amperes, or amps (I) The letter R symbolize resistance, measured in ohms (Ω) To calculate voltage use the equation: V = IR; V (volts) = I (amps) x R (resistance) V = 0.5 A multiplied by 6 ohms = 3 volts (V)
In a 60-cycle alternating current, how many complete cycles are produced every second? 60 180 120 30
60 A 60-cycle alternating current designation indicates that the AC current goes through exactly 60 complete cycles of current alternations in each second. The sine wave illustrates that the current wave starts at zero, reaches a peak on the positive side of the zero axis, returns to zero, continues to another peak on the negative side of the zero axis, and then returns to zero again. One positive and one negative loop represent one cycle or Hz. Thus, 60 Hz current goes through 60 complete sets of these positive and negative loops in one second.
Maximum induction will occur when a conductor cuts a magnetic field at what angle? 180 degrees 45 degrees 90 degrees 0 degrees
90 degrees If a single wire conductor is moved or rotated within a stationary magnetic field, an voltage will be induced within the conductor due to this movement. However, if the conductor moves in parallel with the magnetic field no magnetic lines of flux are cut and no voltage is induced into the conductor, but if the conductor moves at right angles (e.g., 90 degrees) to the magnetic field the maximum amount of magnetic flux is cut producing the maximum amount of induced EMF (voltage). The amount of EMF induced into a coil cutting the magnetic lines of force is determined by the following three factors: (1) the speed at which the coil rotates inside the magnetic field, (2) the strength of the magnetic field, and (3) the number of turns in the conducting coil.
According to the laws of electrostatics, charge is transferred by the movement of photons electrons neutrons protons
electrons According to the laws of electrostatics, some atoms can lose electrons and others can gain electrons; thus it is possible to transfer electrons from one object to another.
