Question

A positron enters a particle accelerator. As it emerges from the accelerator, its mass is measured to be 3.8 × 10^–29 kg. It can be concluded that the positron

A) has become a different particle.
B) is traveling in a circle.
C) is traveling at close to the speed of light.
D) is traveling at a non-relativistic speed.

Answer 1

The measured mass of a positron being greater than its rest mass in a particle accelerator indicates that it is traveling at close to the speed of light due to relativistic effects.

Step-by-step explanation:

The question pertains to the behavior of a positron (the antimatter counterpart of an electron) in a particle accelerator. When a positron is accelerated to high speeds, its mass appears to increase due to relativistic effects, as predicted by Einstein's theory of relativity. The key to the question lies in the concept that, as per relativistic physics, the mass of an object increases as the object approaches the speed of light. This phenomenon occurs due to the object's kinetic energy contributing to its total energy and thus to its relativistic mass.

Given that the measured mass of the positron is greater than its rest mass, which is approximately 9.11 × 10⁻³¹ kg, and since no mention is made of it forming a different particle or moving in a circle, the most plausible conclusion is that the positron (C) is traveling at close to the speed of light. This conclusion aligns with the relativistic effects experienced by particles in accelerators, which are designed to bring particles to incredibly high speeds.