What is meant by "electromagnetism"?

Electromagnetism refers to the interaction between electricity and magnetism, which is fundamental to many concepts in physics and engineering. This interaction arises from the principles of electric charges and magnetic fields, where an electric current creates a magnetic field, and a changing magnetic field can induce an electric current. This phenomenon is essential for the operation of various devices such as motors, generators, transformers, and many electronic components.

Understanding electromagnetism is crucial because it underlies much of modern technology, including communication systems, power generation, and electronic circuits. The principles of electromagnetism are captured in Maxwell's equations, which describe how electric and magnetic fields interact with each other and with matter. This concept is foundational and illustrates the synergy between electricity and magnetism, making option B the correct choice in this context.