Final answer:
The assertion that electromagnets are made of soft iron is correct, as is the reason that the coercivity of soft iron is small, which explains why soft iron is suitable for electromagnets.
Step-by-step explanation:
The assertion that electromagnets are made of soft iron is correct because soft iron is a ferromagnetic material and it is highly suitable for use in electromagnets. This is due to its ability to gain and lose magnetism quickly and easily, which is critical for the operation of an electromagnet. The reason provided, which states that the coercivity of soft iron is small, is also correct and it is a correct explanation for the assertion. Coercivity refers to the resistance of a ferromagnetic material to changes in its magnetic state. Because soft iron has a low coercivity, it can quickly become magnetized and demagnetized, which is desirable in an electromagnet. Therefore, soft iron's small coercivity is directly related to its effectiveness in electromagnets, making it a fitting choice for their construction.