What is reflection of a wave?

The bending of a wave as it passes from one medium to another The spreading of a wave as it passes through a small gap The bouncing back of a wave when it hits a surface, with the angle of reflection equal to the angle of incidence The complete absorption of a wave by a solid material

What is refraction?

The reflection of a wave at a boundary The change in direction of a wave when it crosses a boundary between two media at different speeds The spreading of a wave around the edges of an obstacle The increase in wave amplitude when two waves meet

What is diffraction, and when is it most noticeable?

The reflection of waves off a curved surface The splitting of white light into its component colours The spreading of waves around obstacles or through gaps, most noticeable when the gap size is similar to the wavelength The absorption of wave energy by a medium

Two identical waves meet. Wave A has a crest at a particular point; wave B also has a crest at that same point. What happens?

Destructive interference — the waves cancel completely Constructive interference — the amplitudes add, producing a wave with double the amplitude at that point The two waves merge permanently into one larger wave The waves stop and transfer all their energy to the medium

Wave A has a crest at a particular point; wave B has a trough of equal size at that same point. What happens?

Constructive interference — the crests add together The crest wins because crests are stronger than troughs Destructive interference — the waves cancel, giving zero displacement at that point The waves merge into a new wave with double the frequency

What is a standing wave?

A wave that stays in one place because there is no medium to travel through A wave pattern formed when two identical waves travel in opposite directions and interfere — creating fixed nodes and antinodes A very slow wave produced by large amplitude oscillations A wave that has been reflected so many times its direction is no longer clear

On a standing wave, what is a 'node'?

A point of maximum displacement in a standing wave A point of permanent zero displacement — a position where the wave always has no amplitude The speed of a wave at a particular point The meeting point where two waves collide

What is resonance?

The reflection of sound off a hard surface to produce an echo The large-amplitude response that occurs when a system is driven at its natural frequency The cancellation of sound waves by destructive interference The bending of waves as they pass through different materials

Why can you hear around corners even though you cannot see around them?

Sound is faster than light, so it arrives before the corner blocks it Sound has much longer wavelengths than light — diffraction around a corner is significant only when the obstacle is similar in size to the wavelength Sound passes through walls while light is reflected by them Light is a transverse wave so it cannot bend; sound is longitudinal and can

Noise-cancelling headphones work by detecting ambient noise and producing a cancelling sound. Which wave property do they exploit?

Constructive interference — the headphone amplifies a different sound to mask the noise Resonance — the headphones vibrate at the same frequency as the noise to absorb it Reflection — the headphones bounce noise back toward its source Destructive interference — the headphone produces a wave with the same amplitude but exactly opposite phase to the noise, cancelling it