Can an induced electric field exist in the absence of a conductor?

Understanding how electricity is produced begins with grasping Faraday's Law of electromagnetic induction. This fundamental law discovered by Michael Faraday in the 1830s, tells us that a change in the magnetic field within a closed loop induces an electromotive force (emf) in the loop. The greater the rate of change of the magnetic field, or the larger the area of the loop, the greater the induced emf.

Imagine spinning a loop of wire in a magnetic field; as it rotates, different parts of the loop cut through more or fewer magnetic field lines, and this change is what generates an electric field. When charges are present in a conductor, they respond to this electric field: they start moving along the loop, creating an electric current. However, if there is no conductor, no current can flow, but the electric field is still there, unseen yet potent and ready to act upon any charges that might later be placed in its path.

Electromotive force, commonly abbreviated as emf, is somewhat misnamed because it is not actually a force. The term 'emf' refers to the energy provided to each charge traveling around a circuit. Technically, it's the electric potential generated by either a chemical reaction within a battery or changing magnetic fields, as stated by Faraday's Law.

The moving magnetic fields can induce emf in a loop of wire or even in the air if conditions are right. Various devices, like transformers and generators, rely on this principle to generate and manipulate emf for practical uses such as powering homes and charging batteries. It’s important to differentiate between emf and the voltage; emf is the energy given to charges, whereas voltage is the energy difference that drives charges between two points.

The magnetic environment around us influences many aspects of electricity and magnetism. It refers to the space around which magnetic forces are in effect—the area around a magnetic object where other objects are subject to the force it exerts.

In our everyday lives, Earth itself creates a substantial magnetic environment, as do various devices and machines. When we discuss inducing currents with magnetism, we are referring to the intentional alteration of such environments with tools like magnets, coils, and electrical circuits. As for Faraday's Law, it specifically deals with how changing the magnetic environment can cause an induced electric field, which is a cornerstone in the functioning of many modern technologies, from electric cars to MRI machines.

The flow of electric charge is commonly referred to as electric current, and it is the basis for all of electrical technology. Current is measured in amperes, which indicates the amount of charge passing through a conductor every second.

In more practical terms, think of electric current as the flow of water through a pipe: the water particles are like the charge carriers, and the water flow rate is analogous to the current. In electrical circuits, the conductor (often a wire) acts as the pipe, and the free electrons moving through it are the charge carriers. However, for the flow to happen, just like water needs a pressure difference, electrons need a potential difference, which is usually provided by an electromotive force. Remember, even if an electric field is induced, if the conditions are not suitable for charge carriers to move—meaning if there is no conductor or the circuit is open—then no current will flow.