Which type of radiation has no charge and is unaffected by an electric field?

Gamma radiation is indeed the type of radiation that has no charge and is unaffected by an electric field. It consists of high-energy photons, which are electromagnetic waves. Since gamma rays do not possess either a positive or a negative charge, they are not influenced by electric fields.

In contrast, alpha radiation consists of helium nuclei (two protons and two neutrons) and has a positive charge, making it susceptible to electric fields. Beta radiation comprises negatively charged electrons or positively charged positrons, which also interact with electric fields due to their charge. X-ray radiation, while also a form of electromagnetic radiation, is similarly influenced by electric fields. Therefore, the unique property of gamma radiation being uncharged and unaffected by electric fields is what distinguishes it as the correct answer.