(d) Light and sound

Know that light waves are transverse waves and that they can be reflected and refracted

Use the law of reflection (the angle of incidence equals the angle of reflection)

Draw ray diagrams to illustrate reflection and refraction

Practical: investigate the refraction of light, using rectangular blocks, semi-circular blocks and triangular prisms

Know and use refractive index n = sin i ÷ sin r.

Practical: investigate the refractive index of glass, using a glass block

Describe the role of total internal reflection in transmitting information along optical fibres and in prisms

Explain the meaning of critical angle c

Know and use sin c = 1/n for critical angle c and refractive index n.

Know that sound waves are longitudinal waves that can be reflected and refracted

Know that the frequency range for human hearing is 20–20 000 Hz

Practical: investigate the speed of sound in air

Understand how an oscilloscope and microphone can be used to display a sound wave

Practical: investigate the frequency of a sound wave using an oscilloscope

Understand how the pitch of a sound relates to the frequency of vibration of the source

Understand how the loudness of a sound relates to the amplitude of vibration of the source