Reflection of Circular Waves

When the waves hit the barrier, there is no change in their wavelength (as shown left).

If you're asked to draw this, don't worry about measuring it acurately: merely write WAVELENGTH UNCHANGED in large friendly letters on your diagram!

Key Points

• Circular waves reflect as if from a point exactly the same distance behind the barrier as the source
• There is no change in speed, frequency or wavelength
• Reflected waves the same curvature as if they hadn't changed direction
• Wavefronts join at barrier
• Wave amplitude gets less as they grow, since their energy is more spread out.