Our ancestors relied on fire for light, warmth and cooking. Today at the flick of a switch, turn of a knob or the push of a button, we have instant power. This is possible because of the electric current. Do you know what is current? In this article, let us learn and find how electric current has revolutionised modern-day living. It is one of the important discoveries that helped us transform our way of living. From the time we wake up till the time we sleep at night, our life is dependent on electricity. From the basic bread toaster and baking oven to the commonly used television all require electric current to operate. The most common device, mobile phones, uses the electric current to charge the battery for operation. Besides playing a major part at home, electricity also plays an important role in industries, transportation and communication. In this article, let us learn to define electric current as animportant resource that we are highly dependent on.
- Electric Current Definition
- Prerequisites for the Current to Flow in a Conductor
- What is an Electromotive Force
- Unit of Electric Current
- Visualising Electric Current
- Conventional Current flow Vs Electron Flow
- Properties of Electric Current
- Effects of Electric Current
- Heating Effect of Electric Current
- Magnetic Effect of Electric Current
- Chemical Effect of Electric Current
- Frequently Asked Questions – FAQs
Electric Current Definition
Let us now define electric current and also know about conductors and insulators.
Electric Current is the rate of flow of electrons in a conductor. The SI Unit of electric current is the Ampere.
Electrons are minute particles that exist within the molecular structure of a substance. Sometimes, these electrons are tightly held, and other times they are loosely held. When electrons are loosely held by the nucleus, they are able to travel freely within the limits of the body. Electrons are negatively charged particles hence when they move, a number of charges moves, and we call this movement of electrons as electric current. It should be noted that the number of electrons that are able to move governs the ability of a particular substance to conduct electricity. Some materials allow the current to move better than others.Based on the ability of the material to conduct electricity, materials are classified into conductors and insulators.
Conductors: these materials allow the free flow of electrons from one particle to another. Conductors allow for charge transfer through the free movement of electrons. The flow of electrons inside the conducting material or conductor generates an electric current. The force that is required to drive the current flow through the conductor is known as voltage.
Examples of conductors: Human body, aqueous solutions of salts and metals like iron, silver and gold.
Did You Know?
Silver is the best conductor of electricity.
Insulators: Insulators are materials that restrict the free flow of electrons from one particle to another. The particles of the insulator do not allow the free flow of electrons; subsequently, the charge is seldom distributed evenly across the surface of an insulator.
Examples of Insulators: Plastic, Wood and Glass
Prerequisites for the Current to Flow in a Conductor
Some of the prerequisites for the electric current to flow in a conductor are discussed here.The circuit includes an energy source (a battery, for instance) that produces voltage. Without voltage, electrons move randomly and are undirected; hence current cannot flow. Voltage creates pressure on the electrons, which channelises them to flow in a single direction.
The circuit forms a closed conducting loop through which electrons can flow. A circuit is said to be closed or complete when a switch is turned ON.
What is an Electromotive Force?
The motion of free electrons is normally haphazard. If a force acts on electrons to make them move in a particular direction, then up to some extent random motion of the electrons will be eliminated. An overall movement in one direction is achieved. The force that acts on the electrons to make them move in a certain direction is known as electromotive force, and its quantity is known as voltage and is measured in volts.
Read More: Electromotive Force
Unit of Electric Current
Let us know what is current and the unit to measure it.
The magnitude of electric current is measured in coulombs per second. The SI unit of electric current is Ampere and is denoted by the letter A. Ampere is defined as one coulomb of charge moving past a point in one second. If there are 6.241 x 1018 electrons flowing through our frame in one second, then the electrical current flowing through it is ‘One Ampere.’
The unit Ampere is widely used within electrical and electronic technology along with the multipliers like milliamp (0.001A), microamp (0.000001A), and so forth.
Read More: Ampere
Visualising Electric Current
To gain a deeper understanding of what an electric current is and how it behaves in a conductor, we can use the water pipe analogy of electricity. Certainly, there are some limitations but they serve as a very basic illustration of current and current flow.
Water Pipe Analogy of Electricity
We can compare the electric current to the water flowing through the pipe. When pressure is applied to one end of the pipe, the water is forced to flow through the pipe in one direction. The amount of water flow is proportional to the pressure placed on the end. This pressure can be compared to the electromotive force.
Conventional Current flow Vs Electron Flow
There is a lot of confusion around conventional current flow and electron flow. In this section, let us understand their differences.
Conventional Current Flow vs Electron Flow
Conventional Current Flow
The conventional current flow is from the positive to the negative terminal and indicates the direction in which positive charges would flow.
The electron flow is from negative to positive terminal. Electrons are negatively charged and are therefore attracted to the positive terminal as unlike charges attract.
Properties of Electric Current
After we define electric current, let us learn the properties of electric current. Electric current is an important quantity in electronic circuits. We have adapted electricity in our lives so much that it becomes impossible to imagine life without it.Therefore, it is important to know what is current and the properties of the electric current.
- We know that electric current is the result of the flow of electrons. The work done in moving the electron stream is known as electrical energy. Electrical energy can be converted into other forms of energy such as heat energy, light energy, etc. For example, in an iron box, electric energy is converted to heat energy. Likewise, the electric energy in a bulb is converted into light energy.
- There are two types of electric current known as alternating current (AC) and direct current (DC). The direct current can flow only in one direction, whereas the alternating direction flows in two directions. Direct current is seldom used as a primary energy source in industries. It is mostly used in low voltage applications such as charging batteries, aircraft applications, etc. Alternating current is used to operate appliances for both household and industrial and commercial use.
- The electric current is measured in ampere. One ampere of current represents one coulomb of electric charge moving past a specific point in one second.
- The conventional direction of an electric current is the direction in which a positive charge would move. Henceforth, the current flowing in the external circuit is directed away from the positive terminal and toward the negative terminal of the battery.
You shouldn’t touch electrical equipment with wet hands! Watch the video to know why?
Effects of Electric Current
After defining electric current, let us learn various effects of electric current.When a current flows through a conductor, there are a number of signs which tell if a current is flowing or not. Following are the most prominent signs:
Heating Effect of Electric Current
When our clothes are crumpled, we use the iron box to make our clothes crisp and neat. Iron box works on the principle of heating effect of current. There are many such devices that work on the heating effect.
When an electric current flows through a conductor, heat is generated in the conductor.
The heating effect is given by the following equation
H=I2RT(Video) What is electricity? - Electricity Explained - (1)
The heating effect depends on the following factor:
- The time ‘t‘ for which the current flows. The longer the current flows in a conductor more heat is generated.
- The electrical resistance of the conductor. Higher the resistance, the higher the heat produced.
- The amount of current. The larger the amount of current higher the heat produced.
If the current is small then the amount of heat generated is likely to be very small and may not be noticed. However, if the current is larger then it is possible that a noticeable amount of heat is generated.
Read More: Heating Effect of Electric Current
Magnetic Effect of Electric Current
Another prominent effect that is noticeable when an electric current flows through the conductor is the build-up of the magnetic field. We can observe this when we place a compass close to a wire carrying a reasonably large direct current, and the compass needle deflects. The magnetic field generated by a current is put to good use in a number of areas. By winding a wire into a coil, the effect can be increased, and an electromagnet can be made.
Read More: Magnetic Effect of Electric Current
Chemical Effect of Electric Current
When an electric current passes through a solution, the solution ionizes and breaks down into ions. This is because a chemical reaction takes place when an electric current passes through the solution. Depending on the nature of the solution and the electrodes used, the following effects can be observed in the solution:
- change in the colour of the solution
- metallic deposits on the electrodes
- a release of gas or production of bubbles in the solution
Electroplating and electrolysis are the applications of the chemical effect of electric current.
Frequently Asked Questions – FAQs
Why are copper wires used as connecting wires?
Because they offer low resistivity for the flow of electrons.
What is the reciprocal of conductance?
Resistance is the reciprocal of conductance.
What happens to the resistance of pure metals and semiconductors with an increase in temperature?
The resistance of pure metals increases with the increase in temperature, and the resistance of semiconductors decreases with an increase in temperature.
What is the unit of electric conductivity?
mho/metre or Siemens/metre.
Which method is used for the absolute measurement of resistance?
The Wheatstone bridge method is used for the absolute measurement of resistance.
What are insulators?
Insulators are materials that restrict the free flow of electrons from one particle to another. The particles of the insulator do not allow the free flow of electrons.
Ampere is defined as the unit of electric current that is equal to the flow of one Coulomb per second.
What is electromotive force?
Electromotive force is defined as the electric potential produced by either an electrochemical cell or by changing the magnetic field. EMF is the commonly used acronym for electromotive force.
What is an electric charge?
Electric Charge is the property of subatomic particles that causes it to experience a force when placed in an electric and magnetic field.
State Coulomb’s law.
The magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.
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What is electric current question answer? ›
Electric current is the movement of charges through a conducting medium with respect to time. In Physics, electric current is defined as the flow of charged particles, such as electrons moving through an electrical conductor. The higher the voltage or potential difference, the more the current flow.Which two answers are types of electrical current? ›
There are two kinds of current electricity: direct current (DC) and alternating current (AC). With direct current, electrons move in one direction. Batteries produce direct current. In alternating current, electrons flow in both directions.What is the definition of electric current? ›
Electric current refers to the flow of electricity in an electronic circuit, and to the amount of electricity flowing through a circuit. It is measured in amperes (A). The larger the value in amperes, the more electricity is flowing in the circuit.What energy is electric current? ›
Electrical energy is a type of kinetic energy caused by moving electric charges. The amount of energy depends on the speed of the charges – the faster they move, the more electrical energy they carry.What is the formula for electric current? ›
The formula of electric current is: I =q/t. The SI unit of Electric current is Ampere. The conventional direction of electric current is the direction of motion of the positive charge.What does electric current depend on? ›
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 between two points.What affects electric current? ›
Ohm's law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, if the voltage is increased, the current will increase provided the resistance of the circuit does not change.Which element is used in electric current? ›
Metal wires are used in electric circuits because the metals are good conductors of electricity and allow current to pass through them.How does electric current flow? ›
Current flows from positive to negative and electron flows from negative to positive. Current is determined by the number of electrons passing through a cross-section of a conductor in one second. Current is measured in amperes, which is abbreviated "amps". The symbol for amps is a letter "A".What is the best definition of current? ›
Current is a flow of electrical charge carriers, usually electrons or electron-deficient atoms. The common symbol for current is the uppercase letter I.
What is a current simple definition? ›
Current is the rate at which electrons flow past a point in a complete electrical circuit. At its most basic, current = flow. An ampere (AM-pir), or amp, is the international unit used for measuring current.What is the main type of current? ›
There are mainly two types of current, and they are direct current (DC) and alternating current (AC). The direct current flows in one direction, while the alternating current flows in two directions.What is the first type of current? ›
Interestingly, the first commercial electrical systems set up by Thomas Edison and others were direct current systems.What is responsible for the current to flow? ›
Hence, electrons in the metal are responsible for the flow of current in it.Is electric current solid liquid or gas? ›
Electricity is not a state of matter. It is energy. Specifically, it is energy created by the flow of electrons.Is electric current a wave? ›
So, electricity is not an electromagnetic wave, but can generate a disturbance in the associated electromagnetic field that has the ability to spread like a wave.Is electric current physical or chemical? ›
Passing electricity through a heater's rod is a physical change. This is because, no new substances are formed in this case.What is an electric current created by? ›
An electric current is the movement of particles, starting at the moment when an external voltage is applied at one of the ends of the conductor. That, in turn, generates an electric field on the negatively charged electrons that are attracted to the positive terminal of the external voltage.What is the cause of current? ›
Ocean currents can be caused by wind, density differences in water masses caused by temperature and salinity variations, gravity, and events such as earthquakes or storms. Currents are cohesive streams of seawater that circulate through the ocean.What are examples of electric current? ›
Examples of current electricity are starting a car, turning on a light, cooking on an electric stove, watching TV, shaving with an electric razor, playing video games, using a phone, charging a cell phone and more.
What blocks electric current? ›
Materials that do not let current flow easily are called insulators. Most nonmetal materials such as plastic, wood and rubber are insulators.Why an electric current is needed? ›
Electricity is used to operate your cell phone, power trains and ships, run your refrigerator, and power motors in machines like food processors. Electric energy must be changed to other forms of energy such as heat, light or mechanical in order to be useful.Does current affect power? ›
If you increase the voltage (or electrical pressure) in a circuit, then the current (flow of electrons) will increase in direct proportion, eg if you double the voltage the current flow will double. Therefore double the current multiplied by double the voltage will quadruple the power.What is electric current symbol? ›
The electric current at a point in a circuit is defined as the rate of flow of charge past that point. Electric current is usually represented by the symbol I.Can you have voltage without current? ›
Voltage can exist without current, as it is the cause of flowing charge. Current does not exist without voltage, as voltage is the main cause to flow current except theoretical superconductor.How does electricity move from one place to another? ›
Current electricity happens when electrons flow from one place to another, usually within an electrical circuit. This is because electrons carry electrical energy from one place to another.What is dimension of electric current? ›
I=[M0L0T−1Q]Does current mean charge? ›
Current is the rate of flow of positive charge. Current can be caused by the flow of electrons, ions or other charged particles. Electrons are negatively charged, so the direction electrons flow is the opposite direction to current.How do you measure current? ›
Introduction to Measuring Current
It is measured in the unit of the Ampere, called “Amp,” (A). The most common way to measure current in a circuit is to break the circuit open and insert an ammeter in series (in-line) with the circuit so that all electrons flowing through the circuit must also go through the meter.
Electric Current is the flow of electrons through a wire or solution. In a solid the electrons are passed from one positively charged metallic atom to next but in solution the electron is carried by the ions present in the solution. A solution capable of carrying charge is called an electrolyte.
What is electric current quizizz? ›
Define electric current. It is the work done by the source in driving charges around a complete circuit. It is a measure of the rate of flow of electric charge through a given cross-section of a conductor. It is the work done by the source in driving a unit charge around a complete circuit.What is electric current with example? ›
An electric current is a flow of particles (electrons) flowing through wires and components. It is the rate of flow of charge. If the electric charge flows through a conductor, we say that there is an electric current in the conductor. In the circuits using metallic wires, electrons constitute a flow of charges.Which is the unit for current? ›
The ampere, symbol A, is the SI unit of electric current.How is a current measured? ›
The electric current in one part of a circuit is measured with an ammeter, which gives a reading in ampere. To take the measurement, a gap is made in the circuit and the ammeter is connected into that gap, so that the charged particles moving around the circuit must pass through the meter.What does electricity need to flow? ›
To produce an electric current, three things are needed: a supply of electric charges (electrons) which are free to flow, some form of push to move the charges through the circuit and a pathway to carry the charges. The pathway to carry the charges is usually a copper wire.What does electric current measure? ›
Electrical. Current is the rate at which electrons flow past a point in a complete electrical circuit. At its most basic, current = flow. An ampere (AM-pir), or amp, is the international unit used for measuring current.Is the electric current a magnet? ›
An electric current flowing in a wire creates a magnetic field around the wire, due to Ampere's law (see drawing below). To concentrate the magnetic field, in an electromagnet the wire is wound into a coil with many turns of wire lying side by side.Who described electric current? ›
The I symbol was used by André-Marie Ampère, after whom the unit of electric current is named, in formulating Ampère's force law (1820).