Which term refers to the line representing the undisturbed position of particles when no wave is present?

Which term refers to the line representing the undisturbed position of particles when no wave is present?

• A. Reference line
• B. Baseline
• C. Equilibrium
• D. Origin

Answer: (A)

In wave motion the line where particles settle when there is no disturbance is the equilibrium position—the rest line around which the medium oscillates. It represents zero displacement, so displacement in a wave is measured from this line. The other terms don’t describe the physical resting line: a reference line is a general graphing term, a baseline is also more of a measurement or data term, and the origin is a single point in a coordinate system, not the entire undisturbed line.

In wave motion the line where particles settle when there is no disturbance is the equilibrium position—the rest line around which the medium oscillates. It represents zero displacement, so displacement in a wave is measured from this line. The other terms don’t describe the physical resting line: a reference line is a general graphing term, a baseline is also more of a measurement or data term, and the origin is a single point in a coordinate system, not the entire undisturbed line.