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Voltage and Current are the two fundamental concepts of physics. These two basic quantities are a part of the broader concept of electricity where voltage serves as the primary source, whereas, the current acts as the outcome of the process. As we apply voltage to the circuit, an electric tension generates in the circuit due to potential differences. This tension or pressure then pushes the charged electrons from a battery’s negative terminal to the positive terminal. This movement of electrons is referred to as current. Voltage is responsible for the flow of current. In this article, we will read about the current, voltage, their units, and understand the basic differences between voltage and current.
Read Also: Electric Current and Circuit
| Table of Content |
Keyterms: Voltage, current, Electricity, Circuit, Electron, electric current, electrostatic field, Coulomb, Volt, Joule
Read Also: Difference between Ammeter and Galvanometer
What is Voltage?
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- Voltage is an electrical force, also known as an electromotive force that aids the movement of electrons.
- It is the potential difference between the two points in a circuit.
- This force helps in driving and regulating the electric current between the said terminals of a body.
- The energy-driven in a body on every unit of charge is referred to as the voltage.
- Scientifically, the voltage is symbolized by ‘V’.
- Voltage gives rise to an electrostatic field.
Voltage
SI Unit of Voltage
- The SI unit of voltage is ‘Volt’.
- Here, 1 Volt is equal to 1 Joule per Coulomb
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|---|---|---|
| Electricity Formulas | Electricity Revision Notes | |
| OHM’s Law | Resistance | |
| Unit of Electricity | Unit of Conductivity | |
Formula of Voltage
V = Work Done/Charge
V = W/Q
Types of Voltage
There are two types of voltages:
- Alternating Voltage - It refers to the flow of the voltage which remains alternate and unstable. It is known for shifting its direction and magnitude throughout its flow. This type of voltage is mainly used in devices that convert electrical energy into mechanical energy, especially, electric motors.
Application – Refrigerators, lights, toasters, etc.
- Direct Voltage - It refers to the flow of the voltage which remains constant and unchanged. It is known for flowing in the fixed direction and magnitude throughout its flow. This type of voltage is mainly used in the devices like electrochemical cells/batteries.
Application – Generators, invertors, etc.
Read More: Difference between Series and Parallel Circuits
What is Current?
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- The rate at which the electric charge flows in an electric circuit as driven by the voltage is called current.
- Current is usually measured at a point in time and is always measured in terms of voltage.
- The current is symbolized by ‘I’.
Current
SI Unit of Current
- The SI unit of voltage is ‘Ampere’.
- Here, 1 Volt lies equal to 1 Coulomb per second.
Formula of Current
I = Charge/Time
I = Q/T
Types of Current
There are two types of currents, such as,
- Alternating Current – It refers to the flow that shifts its direction and magnitude throughout its flow.
- Direct Current - It refers to the flow of the current which flows in the fixed direction and magnitude throughout its flow.
Types of Current
Check Important Difference Between Resistance and Resistivity
Difference Between the Voltage and the Current
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Voltage and current are almost complementary to each other and both have their specific functions. Follow the table below to understand the differences between the two.
| Parameters of Differences | Voltage (V) | Current (I) |
|---|---|---|
| Definition | In Physics, scientists have described voltage as an electrical force which is called an electromotive force. This force helps in driving and regulating the electric current between the said terminals of a body. The energy so driven in a body on every unit of charge is referred to as the voltage. | The rate at which the electric charge flows in an electric circuit as driven by the voltage is called current. Current is usually measured at a point in time and is always measured in terms of voltage. |
| SI Units | The SI unit of voltage is ‘Volt’. Here, 1 Volt is equal to 1 Joule per Coulomb | The SI unit of voltage is ‘Ampere’. Here, 1 Ampere is equal to 1 Coulomb per second. |
| Symbol | The Voltage is symbolized by ‘V’. | The current is symbolized by ‘I’. |
| Formula | V = W / Q | I = Q / T |
| Types | Alternating Voltage – It refers to the flow of the voltage which remains alternate and unstable. Direct Voltage - It refers to the flow of the voltage which remains constant and unchanged. | Alternating Current – It refers to the flow of the current that shifts its direction and magnitude throughout its flow. Direct Current - It refers to the flow of the current that flows in the fixed direction and magnitude throughout its flow. |
| Related fields | An Electric/electrostatic field is generated. | A magnetic field is generated. |
| Measured via | Voltmeter | Ampere Meter |
| Generated By | Generators, batteries, etc. | Voltage. |
| Type of Connection in the Series of a circuit | Unequally distributed among the components. | Equally distributed among the components. |
| Cause and Effect Relation | Voltage is the cause behind the current generation. | Current is the effect of the voltage so produced. |
| Interdependency | Voltage nowhere depends on current. | The current completely depends upon the voltage. |
| Parallel Connection | Its magnitude remains constant. | It has different magnitudes in different components. |
| The cause behind the loss | Due to Impedance | Due to Passive Element. |
Voltage, Current, and Resistor
Things to Remember
- The energy generated via the batteries is nothing more than the free movement of the electrons from one electrode to another. And the potential difference between the two electrodes or the two points is known as voltage.
- Therefore, the more efficient and faster is the movement of electrons, the faster shall be the energy released from the batteries, and the faster shall be the flow of the current.
- That is why, it is always considered that the current (I) and the voltage (V) is directly proportional to each other, which means that flow of current increases with the flow of voltage and the flow of voltage increases with the enhanced movement of the electrons.
- And this flow of electrons is enhanced with the help of energy, be it thermal, hydro, or wind.
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Sample Questions
Ques. Explain Voltage. Mention the name of the force associated with voltage? (2 marks)
Ans. In Physics, scientists have described voltage as an electrical force which is called an electromotive force. This force helps in driving and regulating the electric current between the said terminals of a body. The energy so driven in a body on every unit of charge is referred to as the voltage. Scientifically, the voltage is symbolized by ‘V’.
Ques. Define Current. Mention its types. (3 marks)
Ans. The rate at which the electric charge flows in an electric circuit as driven by the voltage is called current. Current is always measured in terms of voltage. The current is symbolized by ‘I’.
There are two types of currents, such as,
- Alternating Current - It refers to the flow of the current which remains alternate and unstable. It is known for shifting its direction and magnitude throughout its flow.
- Direct Current - It refers to the flow of the current which remains constant and unchanged. It is known for flowing in the fixed direction and magnitude throughout its flow.
Ques. Briefly explain the relationship between the current and the voltage. (3 marks)
Ans. Usually, the energy generated via batteries is nothing more than the free movement of the electrons from one electrode to another. And this flow of electrons is enhanced with the help of energy, be it thermal, hydro, or wind. Whereas, the potential difference between the two electrodes or the two points is known as voltage. Therefore, the more efficient and faster is the movement of electrons, the faster shall be the energy released from the batteries, and the faster shall be the flow of the current. That is why, it is always considered that the current (I) and the voltage (V) is directly proportional to each other, which means that flow of current increases with the flow of voltage and the flow of voltage increases with the enhanced movement of the electrons.
Ques. Define Voltage. Mention its types. (3 marks)
Ans. Voltage is an electrical force which is called an electromotive force. This force helps in driving and regulating the electric current between the said terminals of a body. The energy so driven in a body on every unit of charge is referred to as the voltage. Scientifically, the voltage is symbolized by ‘V’. The SI unit of voltage is ‘Volt’. Here, 1 Volt lies equal to 1 Joule per Coulomb.
There are two types of voltages, such as,
- Alternating Voltage – It refers to the flow of the voltage which remains alternate and unstable. It is known for shifting its direction and magnitude throughout its flow.
- Direct Voltage - It refers to the flow of the voltage which remains constant and unchanged. It is known for flowing in the fixed direction and magnitude throughout its flow.
Ques. Explain Current and Voltage with the help of the four major differences between the Current and the Voltage. (5 marks)
Ans. The difference between the two is as follows.
| Parameters of Differences | Voltage (V) | Current (I) |
|---|---|---|
| Definition | Voltage is the force that helps in driving and regulating the electric current between the two terminals of a body. | The rate at which the electric charge flows in an electric circuit as driven by the voltage is called current. |
| SI Units | Volt | Ampere |
| Symbol | V | I |
| Formula | V = Work Done/Charge | I = Charge/Time |
| Types | Alternating Voltage and Direct Voltage | Alternating Current and Direct Current |
Ques. Explain the relation between the volts and the ampere. (2 marks)
Ans. 1 Ampere of current has 12 volts. Moreover, it is always considered that the current (I) and the voltage (V) is directly proportional to each other, which means that the flow of current increases with the flow of voltage, and the flow of voltage increases with the enhanced movement of the electrons.
Ques. What is Direct and Alternating Current? Explain with Examples. (4 marks)
Ans. The rate at which the electric charge flows in an electric circuit as driven by the voltage is called current. C
There are two types of currents, such as,
- Alternating Current – It refers to the flow of the current which remains alternate and unstable. Application – Refrigerators, lights, toasters, etc.
- Direct Current - It refers to the flow of the current which remains constant and unchanged. Application – generators, invertors.
Ques. Which types of fields are generated by the current and the voltage? (1 mark)
Ans. The current generates the magnetic field whereas the voltage generates the electrostatic field.
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