## What is Current and Voltage: Introduction

To explain current and voltage: Current refers to the flow of electric charge through a conductor or circuit, measured in amperes (A). It represents the rate at which charge carriers, such as electrons, move in a specific direction. Current can be either direct current (DC), where charge flows in a constant direction, or alternating current (AC), where the direction periodically reverses.

On the other hand, voltage, measured in volts (V), represents the electrical potential difference between two points in a circuit. It is the driving force that causes the flow of current. Voltage can be thought of as the "pressure" or "push" that pushes the charge carriers along the circuit. Let’s understand this further in detail.

### Defining Current

Current refers to the flow of electric charge through a conductor or circuit. It is the rate at which charge carriers, typically electrons, pass through a given point in a conductor. Current is measured in amperes (A) and is represented by the symbol "I". The direction of current flow is conventionally considered to be from positive to negative, opposite to the actual movement of electrons. Current can be either direct current (DC), where charge flows in a constant direction, or alternating current (AC), where the direction of current periodically reverses. Some characteristics of current are:

Flow of Charge: Current represents the flow of electric charge through a conductor or circuit. It is the movement of charged particles, usually electrons, in a specific direction.

Measured in Amperes: Current is measured in units called amperes (A), named after the French physicist André-Marie Ampère. One ampere is defined as one coulomb of charge passing through a point in a circuit per second.

Types of Current: Current can be either direct current (DC) or alternating current (AC). In DC, the flow of charge is in a constant direction, while in AC, the direction of current periodically reverses due to the alternating voltage.

Relationship with Voltage: Current is directly proportional to voltage according to Ohm's Law. An increase in voltage leads to an increase in current, given a constant resistance in the circuit.

Series and Parallel Current: In a series circuit, the current remains the same at all points as it has only one path. In a parallel circuit, the current is divided among different branches based on the resistance of each branch.

### Defining Voltage

Voltage refers to the electrical potential difference between two points in a circuit. It is the driving force that propels electric charge to flow. Voltage is measured in volts (V) and denoted by the symbol "V". It represents the potential energy per unit charge at a given point. A higher voltage indicates a greater potential difference, providing a stronger push for the charge carriers. Voltage is crucial in determining the behavior and functioning of electrical circuits, including the flow of current and the operation of electronic devices. Some characteristics of voltage are:

Electrical Potential Difference: Voltage represents the difference in electric potential between two points in a circuit. It measures the intensity of the electric field between those points.

Measured in Volts: Voltage is quantified in units called volts (V), named after the Italian physicist Alessandro Volta. One volt is defined as one joule of energy per coulomb of charge.

Symbol: Voltage is typically represented by the symbol "V" in equations and circuit diagrams.

Driving Force: Voltage is the driving force that pushes electric charges to move from a higher potential to a lower potential. It determines the flow of current in a circuit.

Polarity: Voltage has a polarity, indicating the positive and negative terminals. The positive terminal is at a higher potential, while the negative terminal is at a lower potential.

Source of Energy: Voltage is supplied by sources such as batteries, power supplies, generators, or solar cells. These sources create a potential difference to enable the flow of current.

### Current and Voltage Differences

This table provides the main differences between current and voltage. These differences highlight the distinct characteristics of current and voltage, emphasizing their roles and behaviours within electrical circuits.

### Summary

Current and voltage are fundamental concepts in the field of electricity and electronics. Voltage is the potential difference that drives current flow, while current is the actual flow of electric charge. They are interrelated and play vital roles in the functioning of electrical systems. Understanding current and voltage is essential for analyzing and designing electrical circuits, as well as for powering electronic devices and systems.

## FAQs on Difference Between Current and Voltage for JEE Main 2024

1. What is the relationship between current and voltage according to Ohm's Law?

According to Ohm's Law, the relationship between current, voltage, and resistance in an electrical circuit can be defined by the equation V = I * R, where V represents voltage, I represents current, and R represents resistance. Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor. This means that if the voltage increases while the resistance remains constant, the current will also increase. Similarly, if the resistance increases with a constant voltage, the current will decrease.

2. How is voltage created in a circuit, and what role does it play?

Voltage is created in a circuit by a power source such as a battery, generator, or power supply. These devices generate a potential difference between their terminals, establishing a voltage across the circuit. The power source converts other forms of energy, such as chemical energy or mechanical energy, into electrical energy. Voltage plays a crucial role in a circuit as it serves as the driving force that pushes electric charges to flow. It provides the energy necessary to overcome the resistance within the circuit and enables the flow of current. Voltage determines the behaviour and operation of electrical devices and systems, powering electronic components and facilitating the transfer of energy and information.

3. How does current flow in a series circuit, and how is it affected by the components?

In a series circuit, the current has only one path to flow through. The current flow remains the same throughout the circuit since there are no branches or alternative paths. When a power source is connected to the circuit, the current flows from the positive terminal of the source through each component in the circuit and returns to the negative terminal of the source. The components in a series circuit are connected end to end, allowing the current to pass through them sequentially. The current is affected by the components' resistances; as the resistance of the components increases, the current decreases, and vice versa, according to Ohm's Law (I = V/R).

4. How can voltage be adjusted or controlled in an electrical circuit?

Voltage in an electrical circuit can be adjusted or controlled through the use of various devices and techniques. One common method is using variable resistors, such as potentiometers or rheostats, to change the resistance in the circuit, which in turn affects the voltage. Additionally, transformers can be employed to step up or step down the voltage level. Voltage regulators, such as voltage divider circuits or integrated circuits, can be used to maintain a constant voltage output regardless of changes in input voltage or load conditions.

5. Explain the concept of parallel circuits and how current divides among different branches.

In a parallel circuit, multiple branches are connected to the same two points, creating separate paths for current to flow. Each branch offers a different path for the current to follow. The total current entering the junction point divides among the branches based on their respective resistances. According to Kirchhoff's Current Law, the sum of the currents entering a junction point is equal to the sum of the currents leaving it. In a parallel circuit, the voltage across each branch remains the same while the current varies. Branches with lower resistance offer less resistance to current flow, resulting in higher currents, while branches with higher resistance allow less current to pass through.