Which unit is used to measure the magnitude of electrical current? Which unit is used to measure the magnitude of a potential difference? Explain how electrical current and potential difference differ.

The term 'ampere' (symbol: A) is crucial for anyone exploring the field of electricity. It is the standard unit of measurement for electrical current. An intuitive way to understand current is by picturing it as the flow of water through a pipe. In an electrical context, this flow refers to the movement of electric charge.

One ampere is defined as the flow of one coulomb of charge passing through a specific point in an electrical circuit per second. If you imagine an electrical wire, the amount of charge that flows through a cross-section of that wire in one second is measured in amperes. It's like measuring how much water passes a certain point in a river each second. The more charge that flows, the higher the current, and consequently, the higher the number of amperes.

When we talk about 'volt' (symbol: V), we're delving into the concept of potential difference, commonly known as voltage. But what exactly is voltage? Think of it as the push or pressure that motivates electric charge to move from one place to another.

One volt represents the potential difference required to move one coulomb of charge with an energy of one joule. In simpler terms, if you're pushing a boulder up a hill, the harder the push (more work done), the higher the hill (potential difference) you can get it up. Similarly, the more voltage, the more energy per charge and the greater its ability to move the charge through a circuit. This concept is fundamental when designing circuits, as proper voltage is required to ensure that electrical devices function correctly.

The electric charge is the cornerstone of electrical phenomena. It is a property of some subatomic particles, which gives them the ability to exert an electric force on each other. Charges are of two kinds: positive and negative. Like charges repel, while opposite charges attract.

The unit of electric charge is the coulomb (C), named after Charles-Augustin de Coulomb. One coulomb is quite large in terms of the charge an electron or proton carries; it's equivalent to the charge of approximately 6.242 x 10¹⁸ electrons. This property of electric charge underpins the operation of a vast array of devices and is integral to understanding how circuits work. For example, when we measure the flow of charge in a wire and say that it's 1 A, it means an entire coulomb of charge is moving through each second!

An electric field is a fundamental concept in electromagnetism, representing the space around a charged particle where its electric force is felt. You can visualize it as a field of influence that charged objects create in the space around them.

To understand how electric fields work, imagine placing a second charge within the field of a first charge. The second charge will feel a force either pulling it toward the first charge or pushing it away, depending on whether the charges are opposite or similar. The strength of an electric field is measured in volts per meter (V/m). This concept is pivotal because the electric field is what causes electric charges to move, and thus create an electric current when there is a path for it to flow—such as within a wire in an electrical circuit.