What is the formula for wave speed?

If a wave speeds up, what happens to its wavelength?

If a wave slows down, what happens to its wavelength?

What is the name of waves spreading out after going through a gap?

Where can diffraction be seen?

When does significant diffraction occur?

What happens when waves meet a gap in a barrier?

What happens after waves travel through a gap in a barrier?

What does the extent of spreading of waves depend on?

What else does the extent of spreading of waves depend on?

What would a gap much larger than the wavelength cause?

What would a gap similar to the wavelength cause?

What do different materials always have?

What is refraction?

When does refraction occur?

What does refraction depend on?

What materials does refraction occur between?

When a wave enters another material, why does direction change?

Why does direction change during refraction?

What does changing speed of a ray cause, if the ray is travelling at an angle to the normal?

Which part of a wave stays the same when it enters a new material?

What speed do light waves travel at in different materials?

How can you analyse refraction using a glass block?

Which substance is more optically dense?

Which substance is less optically dense?

If a light ray moves from air to glass, what happens to it?

If a light ray moves from glass to air, what happens to it?

What happens when a light ray moves to a new substance?

If a light ray enters a denser substance, what happens to speed?

If a light ray enters a less dense substance, what happens to speed?

If a light ray enters a denser substance, what happens to direction?

If a light ray enters a less dense substance, what happens to direction?

What is the relative speed of a light wave in a dense material?

What is the relative speed of a light wave in a low density material?