A Level Physics Practice Exam

When particles are in antiphase with respect to each other, what does this suggest about their motion?

1. They are moving in the same direction

2. They are moving out of phase

3. They have uniform energy levels

4. They will increase in amplitude

The correct answer is: They are moving out of phase

When particles are said to be in antiphase with respect to each other, this means that they are oscillating in opposite directions at each point in time. In other words, when one particle is at a peak of its motion, the other particle is at a trough, and vice versa. This condition reflects that their motion is out of phase by 180 degrees. Being out of phase indicates a relationship where their displacements from the equilibrium position cancel out at any given moment, leading to an interesting dynamic when energy is exchanged between them. The concept of being in antiphase is frequently encountered in wave phenomena, where it can lead to destructive interference when the waves overlap. Thus, the correct option highlights this concept of antiphase motion as a situation where particles exhibit an opposing phase relationship.