Across
- 5. interrelation of electric currents
- 9. surface curved
- 12. being compressed
- 14. change in direction of propagation of any wave
- 16. sounds caused by the reflection of sound waves from a surface
- 17. curling foamy top of a wave
- 18. a hollow between two wave crests in the sea
- 19. triangular with refracting surfaces at an acute angle
Down
- 1. to vibrate
- 2. automatic
- 3. a force acts on objects at a distance
- 4. throwing back by a body or surface of light, heat, or sound without absorbing it
- 6. extending across something
- 7. one thing absorbs or is absorbed by another
- 8. allowing light to pass through
- 10. diminution in the density of something
- 11. measured from east to west
- 13. not transparent
- 15. a space entirely devoid of matter