Practical Waves

What is reflection?

When a wave bounces off a boundary and changes direction

What is the law of reflection?

Angle of incidence equals angle of reflection

What is the angle of incidence?

The angle between the incoming wave and the normal line

What is the angle of reflection?

The angle between the reflected wave and the normal line

What is a normal line?

An imaginary line drawn at 90° to a surface at the point of incidence

What happens to wave speed in reflection?

It stays the same because the wave remains in the same medium

What is refraction?

The change in direction of a wave due to a change in wave speed when entering a different medium

Why does refraction occur?

Because the wave changes speed when entering a different medium

What happens to frequency in refraction?

It stays the same

What happens to speed and wavelength in refraction?

Both change (speed changes first, wavelength follows)

What happens when a wave enters a more dense medium?

It slows down and bends towards the normal

What happens when a wave enters a less dense medium?

It speeds up and bends away from the normal

What is diffraction?

The spreading out of waves when they pass through a gap or around an obstacle

When is diffraction greatest?

When the gap size is similar to the wavelength

What happens if the gap is much larger than the wavelength?

There is little diffraction

What happens if the gap is smaller than the wavelength?

The wave spreads out a lot

Why does diffraction happen?

Because wavefronts spread out after passing edges or gaps

Give an example of diffraction?

Sound hearing around corners

Does reflection change frequency?

No

Does refraction change frequency?

No

What is the key idea in all wave behaviour?

Energy is transferred, but waves change direction or spread depending on boundaries and gaps