Sound

Learning objectives

• Describe wave generation by vibrating sources, ropes and springs
• Describe ripple-tank waves using wavefronts
• Explain that waves transfer energy
• Explain that wave energy transfer does not transfer matter
• Use amplitude, frequency and wavelength to describe wave motion
• Define and use wave speed and period and interpret wave graphs
• Recall and apply wave speed = frequency × wavelength
• Compare transverse and longitudinal waves and give examples
• Explain sound production by vibration and the need for a medium
• Describe sound using compressions and rarefactions
• Relate sound loudness to amplitude and pitch to frequency
• Explain reflected-sound echoes and use them to measure distance
• Explain ultrasound use in sonar and soft-tissue scanning
• Use the normal, angle of incidence and angle of reflection
• Apply the law of reflection in constructions, measurements and calculations
• Use the normal, angle of incidence and angle of refraction
• Apply sin i divided by sin r as a constant for a fixed pair of media
• Define refractive index as vacuum light speed divided by medium light speed
• Explain the critical angle
• Explain the conditions for total internal reflection
• Apply total internal reflection to optical fibres and state advantages
• Describe how a thin converging lens acts on a light beam
• Define the focal length of a converging lens
• Construct real and virtual image ray diagrams for a thin converging lens
• Describe lens images as real or virtual, magnified or diminished, and upright or inverted