Waves

Worked examples (12)extended set

• 1Amplitude and wavelength from a displacement–distance graph
• 2A longitudinal wave on a spring
• 3Changing the frequency of a ripple tank (multiple choice)
• 4Measuring wavelength and speed in a ripple tank
• 5Show that: the wavelength of a whistle
• 6Prefixes and standard form: GHz and nm
• 7Drawing wavefronts diffracted through a gap
• 8Which wave diffracts most through a doorway? (multiple choice)
• 9Diffraction at the end of a harbour wall
• 10Refraction of water waves at a change of depth
• 11Wave speed from two graphs
• 12Light waves on a scale drawing, then into glass

Model answers (6)

• ✓Model answer — Paper 2/4 short-answer style
• ✓Model answer — Paper 2/4 style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 explanation style
• ✓Model answer — Paper 4 multi-part structured style

Worked examples (12)extended set

• 1Angles and the image in a plane mirror
• 2Multiple choice: the image a lens throws onto paper
• 3A ray reflected by two mirrors at right angles
• 4Refractive index as a ratio of speeds
• 5Refractive index when angles are given from the surface
• 6Critical angle and total internal reflection in a resin block
• 7Multiple choice: when does total internal reflection happen?
• 8Ray diagram for a real image from a converging lens
• 9The magnifying glass: a virtual image
• 10Dispersion by a prism and monochromatic light
• 11Refractive index from a graph of sin i against sin r
• 12Light trapped inside an optical fibre

Model answers (6)

• ✓Model answer — Paper 2/4 short-answer style
• ✓Model answer — Paper 2/4 style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 application style
• ✓Model answer — Paper 4 extended-response style

Worked examples (12)extended set

• 1Completing the electromagnetic spectrum
• 2Multiple choice: matching a region to a use and a danger
• 3Multiple choice: ordering devices by wavelength
• 4Frequency of a laser from its wavelength in nanometres
• 5Wavelength of a wireless-internet signal in GHz
• 6Low-orbit and geostationary satellites
• 7Analogue and digital signals, and regeneration
• 8Multiple choice: which pulse arrives first?
• 9Choosing radiations for communication systems
• 10Wavelength from a scale drawing, then frequency
• 11Signal delay through a geostationary satellite
• 12Two spectral lines: reading wavelengths and finding frequencies

Model answers (6)

• ✓Model answer — Paper 2/4 short-answer style
• ✓Model answer — Paper 2/4 style
• ✓Model answer — Paper 2/4 style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 explanation style
• ✓Model answer — Paper 4 multi-part structured style

Worked examples (12)extended set

• 1Pitch and loudness from oscilloscope traces
• 2Multiple choice: the range both can hear
• 3Compressions, rarefactions and the speed of sound
• 4Show that: wavelength of a parking-sensor pulse
• 5Multiple choice: sound passing from air into water
• 6How long until the bang is heard?
• 7Measuring the speed of sound with echoes
• 8Sonar: a shoal of fish and the seabed
• 9Multiple choice: time for an echo
• 10Two sounds from one tap on a metal railing
• 11Finding a crack in steel with ultrasound
• 12Speed of sound from a distance–time graph

Model answers (6)

• ✓Model answer — Paper 2/4 short-answer style
• ✓Model answer — Paper 2/4 style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 4 structured style
• ✓Model answer — Paper 6 / Paper 4 extended style
• ✓Model answer — Paper 4 multi-part structured style