# Phase change of reflected wave

1. Nov 7, 2007

### pardesi

what do we mean when we say that light wave suffers a phase change of $$\pi$$ when it gets reflected and why does that happen

2. Nov 7, 2007

### Meir Achuz

If it is reflected by a conductor (to make it easy), the E field must be zero at the conductor.
Thus mean that the reflected E field must be equall and opposite to the incident E field.
That is $${\vec E}_R=-{\vec E}_I$$.
In complex notation, -E=exp(i pi) E.

Last edited: Nov 7, 2007
3. Nov 7, 2007

### G01

A phase change of Pi means, in essence, that the wave is flipped upside down after it is reflected. That is, if you have a crest of a wave reflecting off of a boundary, after the reflection, that crest will become a trough. This is due to the electromagnetic boundary conditions at the surface of reflection as Meir Achuz pointed out.

4. Nov 7, 2007

5. Nov 7, 2007

### pardesi

thank u

6. Nov 13, 2010

### azzam154

how do I calculate amplitude and phase for reflected wave? Is the change in phase occurs in all objects

7. Nov 13, 2010