What is the Difference Between Phase difference and Path difference?

The main difference between phase difference and path difference lies in their definitions and the way they are expressed:

• Phase difference: This is the difference in the phase angle of two waves. It is a measure of the difference in the position of the two waves in their respective oscillations, which is usually expressed in radians or degrees.
• Path difference: This is the difference in the distance traversed by the two waves. It is a physical distance between the two sources or points from which the waves originate, and is usually expressed in meters.

The relationship between phase difference and path difference can be derived using the following equation:

$$\Delta x = \frac{\lambda}{2\pi}\Delta \phi$$

where:

• $$\Delta x$$ is the path difference between the two waves
• $$\Delta \phi$$ is the phase difference between the two waves

To express path difference in terms of phase difference, you need to know the wavelength $$\lambda$$ of the associated wave. Conversely, to express phase difference in terms of path difference, you need to know the frequency of the associated wave.

Comparative Table: Phase difference vs Path difference

The main difference between phase difference and path difference lies in their definitions and the way they are measured. Here is a table comparing the two concepts:

In summary, phase difference refers to the difference in phase angles between two waves, while path difference refers to the difference in the distance traveled by two waves. The relation between phase difference and path difference is direct, with phase difference being proportional to the path difference.