physics

2. a note increases if the frequency of the sound wave increases
3. is the change of direction of waves when they travel across a boundary
7. is the spreading out of the waves when they pass through a gap or round the edge of an obstacle
8. takes places only in liquids and gases
9. a renewable sources of energy
10. drive electricity generators in power station
12. waves vibrate parallel to the direction of energy transfer of the waves
13. they let heat pass through easily
14. are echoes that are due to sound waves from a smooth, hard suface

1. is when a liquid turns into a gas
4. waves vibrate at right angles to the direction of energy transfer of the waves
5. is when a gas turns into a liquid
6. is when a light ray as it travels from the air into glass
10. are used to step up power station voltage to the grid voltage
11. radiation is energy transfer by electromagnetic waves