What is an antiparticle? Give an example.

An antiparticle is a particle with the same mass as its corresponding particle, but with opposite charge.

Antiparticles are particles that have the same mass as their corresponding particles, but with opposite charge. For example, the antiparticle of an electron is a positron, which has the same mass as an electron but a positive charge. Similarly, the antiparticle of a proton is an antiproton, which has the same mass as a proton but a negative charge.

Antiparticles were first predicted by Paul Dirac in 1928, as a consequence of his relativistic quantum theory of the electron. The existence of antiparticles was confirmed experimentally in 1932, when Carl Anderson discovered the positron in cosmic rays.

When a particle and its corresponding antiparticle meet, they can annihilate each other, producing energy in the form of gamma rays. This process is used in PET (positron emission tomography) scans, which can be used to image the inside of the body.

Antimatter, which is made up of antiparticles, is rare in the universe, but it can be produced in particle accelerators. The study of antimatter is important for understanding the fundamental nature of matter and energy, and for developing new technologies such as antimatter propulsion for space travel.