If a wave undergoes refraction, what happens to its phase ?

Explanation

To solve the question "If a wave undergoes refraction, what happens to its phase?", we can break it down into the following steps:

### Step 1: Understand Refraction
Refraction is the bending of a wave when it enters a medium where its speed is different. This change in speed causes the wave to change direction.

**Hint:** Remember that refraction occurs due to the change in wave speed as it moves from one medium to another.

### Step 2: Analyze Wave Properties
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