Soft iron is used to make the core of transformer because of it

Answer is D. Soft iron are ferromagnetic materials made of iron which can be magnetized and demagnetized easily. This is an advantage in transformers because in transformers, we're constantly varying magnetism of the core. This is important because without the change of magnetism of the core, there wouldn't be any voltage induced in the second circuit (the output)! Hence, using a soft iron would allow the magnetism of the core to be changed easily, lessening the amount of energy lost and increasing the efficiency of the transformer. Hence, soft iron is used to make core of the transformer.

Transformer Most of the time, you need different AC voltage levels in the electrical system. Sometimes you need low AC voltage, and sometimes high AC voltage is your requirement. You can get both AC volts from a transformer (High and Low). You can use a step-down transformant if your system requires low AC volts from high AC volts. High voltages can be obtained by using step-up transformers. The transformer comprises parts like the winding, core, and body. The transformer also has many types; each type depends on its core. If iron is used as a core in a transformer, it is called an iron core transformer. You will learn in detail about iron core transformers in this article. If air is present as a core in any transformer, it is called an air-core transformer. How does a transformer work? Transformers work by inducing electromagnetic fields according to faraday’s laws. In faraday’s laws of electromagnetic induction, the rules are defined and followed in transformer for converting one energy level to another. It is possible to link two or more electrical circuits using the oscillating magnetic circuit created by the transformer. Mutual induction, or electromagnetic induction, is the principle behind transformer operation. As a result of mutual induction, one coil of wire induces a voltage into another coil that is located near it. An electromagnetic transformer converts voltages or currents between levels in the electromagnetic domain. They are called transformers because the...

Transformers Transformer Construction A typical transformer consists of two coils of wire placed on some type of core material. The composition of a transformer core depends on such factors as voltage, current, and frequency. Size limitations and construction costs are also factors to be considered. Commonly used cores are air and soft iron materials (such as steel). Each of these materials is suitable for particular applications and unsuitable for others. Generally, air-core transformers are used when the voltage source has a high frequency (above about 20kHz). Iron-core transformers are usually used when the source frequency is low (below about 20kHz). A soft-iron-core transformer is very useful where the transformer must be physically small, yet efficient. The iron-core transformer provides better power transfer than does the air-core transformer. An iron-core transformer whose core is constructed of laminated sheets of steel dissipates heat readily; thus it provides for the efficient transfer of power. The steel laminations (see the figure below) are insulated with a nonconducting material, such as varnish, and then formed into a core. It takes about 50 such laminations to make a core an inch thick. The purpose of the laminations is to reduce transformer losses. An important point to remember is that the most efficient transformer core is one that offers the best path for the most lines of flux with the least loss in energy. Core-Type Construction Core-type constructio...