Question

For a wave traveling in the positive X-direction, the particles of higher values of X:
a) lag behind in phase
b) lead in phase
c) have the same phase as may other particle
d) none of the above

Answer 1

If the question appears to be, the wave has lower value of phase.
The phase is defined as the position of a point in time on a waveform cycle.
The phase difference or phase shift as it is also called a Sinusoidal Waveform.

Complete step by step answer:
Phase in sinusoidal function or in waves has two differences, but clearly related. One is the initial angle of sinusoidal function at its origin and is sometimes called phase off it or phase difference. Another usage is the fraction of wave cycle that has elapsed relative to the origin.
Amplitude is distance from the rest position to crest position which is half the vertical distance from trough to crest and amplitude in simple harmonic progressive wave is the amplitude displacement from the equilibrium position in simple harmonic progressive wave amplitude and displacement are related in following wave
$x = A\sin (wt)$.

So, the correct answer is “Option B”.

Note:
A leading phase means a waveform is ahead of another wave with some frequency and lagging phase means a waveform is behind another wave when the phase difference between two wave is${90^0}$, then that phase is said to be in phase quadrature and when the phase difference between two wave is ${180^0}$ then the waves are said to be in phase position. The phase difference or phase shift as it is also called a Sinusoidal Waveform is the angle $\phi$ (Greek letter Phi), in degree or radians that the waveform has shifted from a certain reference point along the horizontal zero axis.