The ability of any conductor in an electrical circuit to pass current is judged by its electrical RESISTANCE. Resistance is the ability to OPPOSE the flow of electric current.
What is the difference between resistance and conductor?
A conductor is any material that will allow an electrical current to flow through it. The ability of any conductor in an electrical circuit to pass current is judged by its electrical RESISTANCE. Resistance is the ability to OPPOSE the flow of electric current.
What is the ability of a conductor to pass current?
The ability of any conductor in an electrical circuit to pass current is judged by its electrical RESISTANCE. Resistance is the ability to OPPOSE the flow of electric current.
What is the relationship between resistance and voltage?
Voltage is the electrical force that causes current to flow through a conductor, but the greater the value of resistance of any conductor, the less current will flow for any particular value of voltage applied. The resistance of a conductor depends mainly on three things: 1. The LENGTH of the conductor.
Why does current flow less in a longer conductor?
Because the resistance is greater in longer conductors than in shorter ones, then: and is written as R ∝ L (∝ means proportional to...) Therefore the longer the conductor, the more resistance is present and so less current flows. Also, because resistance is less in conductors with a large cross sectional area:
Why should a resistance circuit have an adjustable limiting resistor?
What does a FET transistor do?
Why do materials have no movement?
What is the energy of atomic vibration?
Why is conductance off metal?
How does electric induction change a metal?
What happens if you have a perfect conductor?
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What happens when an electric current passes through a conductor?
An electric current flowing through a conductor produces magnetic field in its surrounding region.
When a current flows through a conductor its resistance?
The higher the resistance of the conductor, the higher will be the heat produced. The heat produced is proportional to the time for which the current is flowing through the conductor. The amount of heat generated also depends on the amount of current flowing through the conductor.
What happens to current when it passes through a resistance?
We all know that in a series circuit, the current is the same for all of the elements. But when the current flow through a resistor, what does it lose? The current is the same because it doesn't lose the numbers of charges.
What causes resistance to electricity through a conductor?
Resistance is caused in a conductor by the free electrons. These free electrons collide with each other and with the ions and atoms that oppose their free movement. This obstruction is known as resistance.
When current flows through a conductor?
When an electric current flows through a conductor it becomes hot.
When current flows in a conductor?
One amp is defined as 6.28 x 10 18 electrons per second. When current flows in a conductor, heat is produced. This happens because every conductor offers some resistance to current flowing. That is why the amperage flow in a circuit is important, since the more amps flowing, the more heat is produced.
How does resistance decrease current?
The atoms in a resistor scatter and absorb the energy from the charge carriers in the current. So some of the average kinetic energy of the current is converted to heat in the resistor, and the current is reduced, compared to if the resistance wasn't there.
Does current decrease as it passes through a resistor?
So yes, the resistor does reduce the current.
Does resistance change the current?
Ohms law states that the current flowing in a circuit is proportional to the voltage applied to the circuit, and inversely proportional to the resistance of the circuit. In other words, for a given voltage, the current in the circuit will decrease as the resistance increases.
What is electric resistance of a conductor?
The electrical resistance of a conductor may be defined as the basic property of any substance due to which it opposes the flow of current through it.
What is the resistance of a conductor?
The resistance of a conductor is defined as the ratio of the potential difference across its end to the current flowing through it. Its SI unit is ohm (Ω).
What is resistance in electric current?
Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). Ohms are named after Georg Simon Ohm (1784-1854), a German physicist who studied the relationship between voltage, current and resistance.
What is the main cause of resistance?
Cause of Resistance in a Conductor: Flow of electrons in a conductor is electric current. The positive particles of conductor create hindrance to flow of electrons, because of attraction between them; this hindrance is the cause of resistance in the flow of electricity.
What are the 4 factors affecting the resistance of a conductor?
There are four factors affecting resistance which are Temperature, Length of wire, Area of the cross-section of the wire, and nature of the material.
What factors affect the resistance of a conductor?
There are several factors that affect the resistance of a conductor;material, eg copper, has lower resistance than steel.length - longer wires have greater resistance.thickness - smaller diameter wires have greater resistance.temperature - heating a wire increases its resistance.
What factors does the resistance of a conductor depends?
The resistance of a conductor depends upon the resistivity, length and cross-sectional area of the conductor which is given by the relation (R=ρAl). It does also depend on other physical factors like temperature etc. Its SI unit is Ohm (Ω).
What is the relationship between resistance and conductance?
Therefore, the resistance and conductance of objects or electronic components made of these materials is constant. This relationship is called Ohm's law, and materials which obey it are called ohmic materials. Examples of ohmic components are wires and resistors.
What is the purpose of resistors?
Resistors (and other elements with resistance) oppose the flow of electric current; therefore, electrical energy is required to push current through the resistance. This electrical energy is dissipated, heating the resistor in the process.
What are resistors made of?
Resistors, on the other hand, are made of a wide variety of materials depending on factors such as the desired resistance, amount of energy that it needs to dissipate, precision, and costs.
What is superconductivity?
Superconductors are materials that have exactly zero resistance and infinite conductance, because they can have V = 0 and I ≠ 0. This also means there is no joule heating, or in other words no dissipation of electrical energy. Therefore, if superconductive wire is made into a closed loop, current flows around the loop forever. Superconductors require cooling to temperatures near 4 K with liquid helium for most metallic superconductors like niobium–tin alloys, or cooling to temperatures near 77 K with liquid nitrogen for the expensive, brittle and delicate ceramic high temperature superconductors . Nevertheless, there are many technological applications of superconductivity, including superconducting magnets .
How does alternating current flow through a circuit?
When an alternating current flows through a circuit, the relation between current and voltage across a circuit element is characterized not only by the ratio of their magnitudes, but also the difference in their phases. For example, in an ideal resistor, the moment when the voltage reaches its maximum, the current also reaches its maximum (current and voltage are oscillating in phase). But for a capacitor or inductor, the maximum current flow occurs as the voltage passes through zero and vice versa (current and voltage are oscillating 90° out of phase, see image below). Complex numbers are used to keep track of both the phase and magnitude of current and voltage:
What is the relationship between electrical conductors and rubber?
Objects made of electrical insulators like rubber tend to have very high resistance and low conductivity, while objects made of electrical conductors like metals tend to have very low resistance and high conductivity. This relationship is quantified by resistivity or conductivity.
What is a thermometer made of?
(A resistance thermometer is made of metal, usually platinum, while a thermistor is made of ceramic or polymer.)
How does a transformer affect the voltage?
Transformer induces the voltage into primary coil over into a secondary coil this will force electrons to flow if coil in secondary side as closed circuit. In transformer we can increase or decrease the voltage between the primary and secondary coil simply by changing amount of coil on the either side.
How does wrapping a coil increase the strength of a magnetic field?
We can increase the strength of magnetic field by wrapping the coil around the iron core, also by increasing the number of turns of coils and also by increasing the amount of the current in the circuit.
What happens when a circuit is closed?
The circuit will open or close, in closed circuit electrons will flow around, in open circuit electrons will not able to flow. Voltage is pushing force of electrons in a circuit like a pressure in a water pipe more pressure more water will flow, if less pressure less water will flow.
How does an induction motor work?
This is how electromagnets works and this basis the induction motor works. When magnetic field passes across the wire it will induces the voltage in their wire. The induced electromagnetic force will push the electrons in certain direction. Learn More: Fleming Left Hand Rule- Easy Remembering Tips.
Why are materials different?
Materials are just different because the construction of atom is slightly different. The atoms are made from free particles which are found from the center of the nucleus and free particles are found outside of the nucleus. Center of the atom the nucleus is present in nucleus the neutrons are present which have no charge.
How to measure the flow of electrons?
To measure the flow of electrons we can use the unit as Ampere. 1 Amp = 1 coulomb/sec. 1 coulomb – group of electrons. The group is incredibly large approximately 6 billion 242 millions of electrons has to pass in 1 second. That’s why electrons are group together that makes ampere to make easier for engineers.
Which part of an atom has no charge?
Center of the atom the nucleus is present in nucleus the neutrons are present which have no charge. And have the proton which is positively charge. The neutrons and protons heavier the electrons these will stay in nucleus. Surrounding the nucleus different layers of orbital shell these are all free pass electrons.
How to find the cross sectional area of a conductor?
If the cross section of the conductor is square or rectangular, the cross sectional area of the conductor can still be found by simply multiplying the width by the height. Most conductors, found in cables etc. are of course circular in cross section.
What is the difference between a conductor and a resistor?
A conductor is any material that will allow an electrical current to flow through it. The ability of any conductor in an electrical circuit to pass current is judged by its electrical RESISTANCE. Resistance is the ability to OPPOSE the flow of electric current. Voltage is the electrical force that causes current to flow through a conductor, ...
What causes current to flow through a conductor?
Voltage is the electrical force that causes current to flow through a conductor, but the greater the value of resistance of any conductor, the less current will flow for any particular value of voltage applied. The resistance of a conductor depends mainly on three things:
What does R L mean?
and is written as R ∝ L (∝ means proportional to...) Therefore the longer the conductor, the more resistance is present and so less current flows. Also, because resistance is less in conductors with a large cross sectional area:
How much energy does a 9 volt battery release?
Defined in these scientific terms, 1 volt is equal to 1 joule of electric potential energy per (divided by) 1 coulomb of charge. Thus, a 9-volt battery releases 9 joules of energy for every coulomb of charge moved through a circuit.
What is the main discovery of Ohm?
Ohm’s principal discovery was that the amount of electric current through a metal conductor in a circuit is directly proportional to the voltage impressed across it, for any given temperature. Ohm expressed his discovery in the form of a simple equation, describing how voltage, current, and resistance interrelate:
What is the relationship between current, voltage, and resistance called?
Chapter 2 - Ohm's Law . The first, and perhaps most important, the relationship between current, voltage, and resistance is called Ohm’s Law, discovered by Georg Simon Ohm and published in his 1827 paper, The Galvanic Circuit Investigated Mathematically.
What is the symbol for electric charge?
The symbol for electric charge quantity is the capital letter “Q,” with the unit of coulombs abbreviated by the capital letter “C.”. It so happens that the unit for current flow, the amp, is equal to 1 coulomb of charge passing by a given point in a circuit in 1 second of time.
What is the opposition to motion called?
Current tends to move through the conductors with some degree of friction, or opposition to motion. This opposition to motion is more properly called resistance. The amount of current in a circuit depends on the amount of voltage and the amount of resistance in the circuit to oppose current flow. Just like voltage, resistance is a quantity relative ...
What is Coulomb in electrical measurement?
One foundational unit of electrical measurement often taught in the beginnings of electronics courses but used infrequently afterward, is the unit of the coulomb, which is a measure of electric charge proportional to the number of electrons in an imbalanced state.
What does the symbol "V" mean?
The symbols “E” and “V” are interchangeable for the most part, although some texts reserve “E” to represent voltage across a source (such as a battery or generator) and “V” to represent voltage across anything else.
What does doubling the cross sectional area of a wire mean?
But, remember that L is in terms of metres and A is in terms of sq. metres. So, doubling the cross sectional area of (circular) wire means increasing radius of wire by sq. root of 2 or simply 1.4142.
What happens to the resistance of a conductor when the current is doubled?
When the current is doubled, the power dissipation is quadrupled. But nothing happens to the resistance of the conductor, unless it gets so hot that the resistance is affected by the temperature. Absolutely nothing unless the power dissipated across the resistor exceeds its rated wattage.
Why should a resistance circuit have an adjustable limiting resistor?
The resistance circuit should have an adjustable limiting resistor to compensate for battery aging. There could be shunts across the galvanometer to allow a wide range of currents to be measured. There may be aseveral series resistors in the voltage circuit to allow for a wide range of voltages…. Related Answer.
What does a FET transistor do?
In simple terms this type of transistor uses the field produced by the voltage to control a separate current through it provided by a battery, and indeed this is the basis on which many practical voltmeters work.
Why do materials have no movement?
Normally all materials have vibrating electrons as they heat up which is the reason to cool down materials to absolute zero (no movement) in order to get the lowest possible resistance or super conductor.
What is the energy of atomic vibration?
Atomic vibration energy is what we know as heath, and its itensity is temperature. Vibration spreads trough the solid as is known the heath spreads. Flowing from high temperature places to low temperture ones. On resistances, temperature rises until heat flow to ambient equals heat produced on resistance.
Why is conductance off metal?
It is conducted off the metal because it is a reflection that must be bounded and directed by something reflective to light as a mirror does. So the best term for metal wires and metallic surfaces is reflector or obstructor and not conductor. Conductance flows through the insulating material and avoids the metal.
How does electric induction change a metal?
All the rays of electric induction reenter and penetrate the intermolecular dimension of the metal, transforming into heat by the process of friction or change in medium, from the space surrounding the metal (which is really where the electric field wants to be) to the intern-molecular structure of the metal.
What happens if you have a perfect conductor?
If you have a perfect conductor all the electric field created around the surface of the conductor is maintained ”floating” outside the conductor and by not being allowed to penetrate into the conductor material it is not consumed by friction , hence no “electrons”.
Overview
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is electrical conductance, measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (Ω), while electrical conductance is measured in siemens (S) (formerl…
Introduction
In the hydraulic analogy, current flowing through a wire (or resistor) is like water flowing through a pipe, and the voltage drop across the wire is like the pressure drop that pushes water through the pipe. Conductance is proportional to how much flow occurs for a given pressure, and resistance is proportional to how much pressure is required to achieve a given flow.
The voltage drop (i.e., difference between voltages on one side of the resistor and the other), not …
Conductors and resistors
Substances in which electricity can flow are called conductors. A piece of conducting material of a particular resistance meant for use in a circuit is called a resistor. Conductors are made of high-conductivity materials such as metals, in particular copper and aluminium. Resistors, on the other hand, are made of a wide variety of materials depending on factors such as the desired resistance, …
Ohm's law
For many materials, the current I through the material is proportional to the voltage V applied across it:
Other components and materials used in electronics do not obey Ohm's law; the current is not proportional to the voltage, so the resistance varies with the voltage and current through them. These are called nonlinear or non-ohmic. Ex…
Relation to resistivity and conductivity
The resistance of a given object depends primarily on two factors: what material it is made of, and its shape. For a given material, the resistance is inversely proportional to the cross-sectional area; for example, a thick copper wire has lower resistance than an otherwise-identical thin copper wire. Also, for a given material, the resistance is proportional to the length; for example, a long coppe…
Measurement
An instrument for measuring resistance is called an ohmmeter. Simple ohmmeters cannot measure low resistances accurately because the resistance of their measuring leads causes a voltage drop that interferes with the measurement, so more accurate devices use four-terminal sensing.
Static and differential resistance
Many electrical elements, such as diodes and batteries do not satisfy Ohm's law. These are called non-ohmic or non-linear, and their current–voltage curves are not straight lines through the origin.
Resistance and conductance can still be defined for non-ohmic elements. However, unlike ohmic resistance, non-linear resistance is not constant but var…
AC circuits
When an alternating current flows through a circuit, the relation between current and voltage across a circuit element is characterized not only by the ratio of their magnitudes, but also the difference in their phases. For example, in an ideal resistor, the moment when the voltage reaches its maximum, the current also reaches its maximum (current and voltage are oscillating in phase). But for a c…