Across
- 3. , the lowest temperature at which a substance catches fire.
- 6. above ---dB the noise becomes physically painful.
- 7. the substances which catches fire at very low temperature.
- 12. the greater the amplitude ,the sound will be.
- 15. the --- the frequency, the lower the pitch.
- 16. oxides of sulphur and nitrogen dissolves in rainwater to produce
- 17. sound waves are--- waves.
- 18. sound travels slowest through.
- 19. non metal which catch fire if exposed to air.
- 20. wave, ---- happens when air molecules goes back and forth.
Down
- 1. amount of energy produced on complete combustion of 1 kg of fuel.
- 2. unburnt particles are present in this zone.
- 4. sound travel faster in --- temperature.
- 5. used for extinguish fire due to electricity or oil.
- 8. quick burning with lot of heat and light.
- 9. ---- is measured from 2 compression or 2 rarefaction.
- 10. the loudness is expressed in a unit called.
- 11. the most corrosive gas.
- 13. three bones of middle ear is called.
- 14. dry powder of chemical is used in fire extinguisher.