What is the primary function of an antenna?

The primary function of an antenna is to radiate or collect electromagnetic energy. Antennas are specially designed components that can convert electrical energy into electromagnetic waves, which are then transmitted through the air, or vice versa—receiving incoming electromagnetic waves and converting them back into electrical energy. This principle is fundamental in various communication systems, including radio, television, and mobile communications.

When considering the context of the other options, conducting electricity pertains more to materials used in the fabrication of antennas, rather than their main role. Similarly, amplifying sound waves relates to audio technology rather than the functionality of antennas, which deal with electromagnetic signals instead. Filtering signal noise may be relevant in the context of signal processing but does not define the intrinsic purpose of an antenna. Thus, the correct choice highlights the essential capability of antennas to interact with and manipulate electromagnetic energy.