Question

Explain the working of solenoid.

Answer 1

Hint: We know that solenoid is a coil of wire which converts electrical energy into mechanical energy. We will discuss in more detail about the definition of solenoid and its working.

Complete step by step solution:
A wire coil used as an electromagnet is known as a solenoid. It also refers to any device that converts electrical energy to mechanical energy through a solenoid. The machine induces a magnetic field from electric current and uses the magnetic field to achieve linear motion.
A solenoid is a coil of wire bound across a corkscrew-shaped piston, usually made of iron.
Electromagnets have the advantage over permanent magnetic materials in that they can be switched on and off by changing the electrical field, making them useful as controls and switches that can be automated.
The positive and negative poles of an activated solenoid's magnetic field attract or repel sensitive material from the magnets.
The electrical force causes the piston within a solenoid to move forward or backward, which is how motion is created.
Consider a solenoid whose length is high in comparison to its radius. The wire is wrapped in the form of a helix with a very small gap between any two turns. The wires are enamelled as well, insulating them from one another. As a result, each turn can be viewed as a closed circular loop. The total magnetic field produced by the solenoid can be defined as the amount of vector force provided by each such turn, and the total magnetic field created by the solenoid is equal to that formed by a circular loop. The figure below depicts the lines of magnetic fields produced within a finite solenoid.

The magnetic field inside the solenoid is constant and runs along the solenoid axis, as seen in the diagram above. The field at any point beyond the solenoid is very thin, and the field lines can't be seen in the immediate vicinity. It's important to remember that the field inside is parallel to its axis at all times.
The magnetic force produced by a solenoid can be defined using the Law of the Ampere as follows:
\[F={{\mu }_{0}}nI\]
Where
${{\mu }_{0}}$= permeability of free space
$n$= number of turns of the wire per unit length
$I$ = current flowing through the wire
Using the right-hand thumb rule the direction is given.

Note:
One must know that with all electromagnets, when an electric current passes via the wire a magnetic field is generated; solenoid converts electrical energy to mechanical energy and this energy is used to operate a mechanical valve that is to open, close or to adjust in a position.