Final answer:
True, only charged particles can be accelerated in a linear accelerator due to their interaction with the alternating electric fields, which is a necessity for the acceleration process.
Step-by-step explanation:
Only charged particles can be accelerated in a linear accelerator. This statement is true. A linear accelerator, also known as a linac, uses alternating electric fields to accelerate charged particles such as electrons and protons. These particles are injected at one end of a long evacuated tube, and the alternation of the electric fields propels the particles forward, increasing their speed dramatically. The efficiency of the acceleration process in a linear accelerator relies heavily on the presence of an electric charge on the particles because the accelerating electric fields exert a force on charged particles as described by Coulomb's law. Neutral particles, on the other hand, would not respond to these electric fields and, therefore, cannot be accelerated using this method.
Similarly, concepts like wave-particle duality, electromagnetic radiation like visible light causing the photoelectric effect, and the ability of gravity to bend a beam of light are all related to the fundamental principles of physics such as quantum mechanics and general relativity that govern how particles and energy interact with each other and with fields, including gravitational and electromagnetic fields.