Question

The materials suitable for making electromagnets should have:

A. High retentivity and high coercivity.

B. Low retentivity and low coercivity.

C. High retentivity and low coercivity.

D. Low retentivity and high coercivity.

Answer 1

Hint: An electromagnet is a substance that induces a magnetic field with the help of an electric field. In this question, we will first define electromagnets and then we will define their properties. Also, we will define the terms coercivity and retentivity to come to the answer. 

Complete answer:

An electromagnet is a substance that uses the electric field to produce the magnetic field around it. We can change the strength of an electromagnet by changing the amount of electric field through it. The structure of an electromagnet consists of a core of iron on which a coil of wire is wounded. Now, the strength of the magnetic field generated is proportional to the amount of the electric current. Therefore, the strength of the magnetic field changes with the change in the amount of the electric current. Hence, this is the advantage of an electromagnet over the permanent magnet. Now, let us define the terms coercivity and retentivity.

Coercivity: coercivity is defined as the intensity of electromagnetic force that should be minimum. The magnetizing intensity is the intensity that is used to bring the electromagnet to its original path. The coercivity of an electromagnet should be low because if the coercivity is high then it will be difficult to control the magnetic field of the electromagnet.

Retentivity: It is the ability of electromagnet which means that the electromagnet remains magnetized even after the removal of the magnetic field. The retentivity of an electromagnet should be low so that after removing the electric current to the substance doesn’t get magnetized and return to its original state.

Hence, the materials suitable for making electromagnets should have low retentivity and low coercivity. Therefore, option B is the correct option. 

Note: An electromagnet is a substance that heats up very quickly. Also, they can consume a large amount of energy. The electromagnets are widely used in particle accelerators, amplifiers, magnetic separation, electric motors and generators, MRI machines, hard drives, etc.