Induced EMF is the electric force that is generated in a conductor (like a wire) when it experiences a changing magnetic field. This changing magnetic field causes electricity (or an electric current) to flow through the conductor.
- EMF is like the “push” that moves electric charges (electrons) in a wire. It is the energy that causes current to flow.
- Induced means that this EMF (or push) is caused by something happening in the surroundings—specifically, a change in the magnetic field.
When a magnet moves near a wire or when the strength of a magnetic field around a wire changes, it makes the electrons inside the wire move. This creates a flow of electricity (current) in the wire. This is called induced EMF because the electric force (EMF) is not directly applied (like in a battery), but rather induced by the changing magnetic field.
Examples of Induced EMF:
- Moving a Magnet Near a Wire: If you move a magnet in and out of a coil of wire, you will generate an electric current in the wire. The faster you move the magnet, the stronger the induced EMF.
- Rotating a Coil in a Magnetic Field: If you spin a coil of wire inside a magnetic field, the changing magnetic field induces an EMF, which causes a current to flow in the wire.
Uses of Induced EMF:
Induced EMF is the principle behind many everyday technologies. Here are some important uses:
Electric Generators: When a magnet moves past a coil of wire (or a coil moves in a magnetic field), induced EMF is created, which generates electricity.
Power plants use this principle to create electricity for homes, schools, and businesses.
Electric Motors: Electric motors use induced EMF to convert electrical energy into mechanical energy (motion). When electric current flows through a wire in a magnetic field, it creates a force that makes the motor spin. Electric motors are used in appliances like fans, washing machines, and even in electric cars.
Transformers: Transformers use induced EMF to change the voltage of electricity. They work by using alternating current (AC) to create changing magnetic fields in one coil, which induces EMF in another coil to either increase or decrease the voltage. Transformers are used in power lines to increase or decrease voltage for efficient transmission of electricity over long distances.
Induction Cooking: In induction cooktops, alternating current flows through a coil to create a changing magnetic field, which then induces an electric current in the metal cookware. This current heats the pot directly. Induction cooktops are more energy-efficient and faster than traditional electric stoves.
Wireless Charging: Wireless chargers use a magnetic field to induce an EMF in a coil inside your phone or device, transferring energy without direct contact. This is used in devices like smartphones, electric toothbrushes, and even electric cars.
- Induced EMF is the electric force created when a magnetic field changes around a conductor.
- This principle is used to generate electricity in generators, run motors, transfer power with transformers, and power devices like induction cookers and wireless chargers.
