What type of field travels through space after being detached from the current-carrying rod of an antenna?

The correct choice is the radiation field, which refers to the electromagnetic field that propagates through space as a result of accelerating charges, such as those found in an antenna. When an alternating current flows through an antenna, it creates varying electric and magnetic fields. Once the current ceases or detaches from the antenna, the electromagnetic waves generated can continue to travel through space.

This phenomenon occurs because electromagnetic radiation is formed when the electric and magnetic fields oscillate and move away from the source. The radiation field is characterized by its ability to carry energy away from the antenna, and it can propagate through a vacuum, which is critical for communication technologies that rely on radio waves.

In contrast, while induction fields, electric fields, and magnetic fields are essential concepts within electromagnetic theory, they do not effectively describe the waves that travel through space independently of the current-carrying source after the current stops. Induction fields, for instance, typically relate to the influence of a magnetic field on a nearby conductor. Electric and magnetic fields, while they are components of electromagnetic radiation, do not propagate through space as standalone fields once the antenna is disconnected from the current.