The wave front is a surface in which

The wave front is a surface in which
  1. all points are in the same phase
  2. there are pairs of points in opposite phase
  3. there are pairs of points with phase difference (π/2)
  4. there is no relation between the phases

Solution

A wave front is a surface over which an optical wave has a constant phase (i.e. there is no phase difference).
Or such a surface which envelopes the particles that are in the same state of vibration is known as a wave front.
The wave front at any instant is defined as the locus of all the particles of the medium which are in the same state of vibration.

Asked in: AP EAMCET 2021 (20 Aug Shift 2)

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