Question

What is an electromagnet? Name two factors on which the strength of the magnetic field of an electromagnet depends on.

Answer 1

Hint: To solve this question one must understand the relation between the electric current and magnetic field of an electromagnet. It is a device that is used to obtain a magnetic field from an electric current. Since the magnetic field is produced as a result of the flow of current, once it is switched off there will no longer be a magnetic field.

Complete step by step answer:
An insulated copper wire when wound about a soft iron core in the shape of a solenoid gives us an electromagnet. An electromagnet is one in which a magnetic field is produced from an electric current. However, when the current is switched off the magnetic field will disappear. By controlling the current flowing through the electromagnet, the magnetic field can be changed or altered. The SI unit of a magnetic field is Tesla. The unit of the magnetic field can also be expressed in terms of Gauss.
An electromagnet’s magnetic field strength depends on
The current flowing through the wire
The number of turns of wire wound about the coil.
Electromagnets are usually in the form of solenoids.
The magnetic field can be expressed as ${\text{B}} = {{{\mu }}_{\text{o}}}{\text{nI}}$ and ${\text{n}} = \dfrac{{\text{N}}}{{\text{L}}}$
\[B = \] Magnetic field
\[n = \] Number of turns per unit length
\[I = \] Current
From the equation, we observe that the magnetic field is directly proportional to the current and number of turns per unit length.
Therefore with an increase in the current and the number of turns, the magnetic field will also increase.

Note: By reversing the flow of the electric current one can reverse the pole (The North Pole and The South Pole) of an electromagnet. Electromagnets are used in particle accelerators, MRI machines, hard drives, and many others. Unlike the permanent magnet, the strength of the magnetic field of an electromagnet can be altered. However, electromagnets heat up rapidly and consume a lot of energy.