Across
- 2. this increases if the frequency of the sound increases
- 6. vibration that travels through a substance
- 7. the change of direction of a light ray when it passes across a boundary between two transparent substances
- 9. electric and magnetic disturbances that transfer energy
- 13. angle between the reflected ray and the normal
- 15. wave in which the vibration is perpendicular to the direction of energy transfer
- 17. waves in which the vibrations are parallel to the direction of energy transfer
- 18. the angle between the incident ray and the normal
Down
- 1. sound wave at a frequency greater than 20 000Hz
- 3. height of a wave crest or trough of a transverse wave
- 4. the spreading of waves when they pass through a gap or around the edges of an obstacle
- 5. reflection of sound that can be heard
- 8. at right angles
- 10. stretched apart
- 11. the distance from one wave crest to another
- 12. squeezing together
- 14. the number of wave crests passing a fixed point every second
- 16. distance moved / time taken