Fig. 1 shows an ear defender used by a ground crew member near an aircraft. A microphone records the sound outside and inside the defender. The sound level ...
Question 1 Report
Fig. 1 shows an ear defender used by a ground crew member near an aircraft. A microphone records the sound outside and inside the defender. The sound level outside is 98 dB and the sound level inside is 76 dB.
(a) Calculate the reduction in sound level caused by the ear defender. [1]
(b) State which sound wave property is mainly reduced by the ear defender. [1]
(c) Explain why long exposure to very loud sound can damage hearing. [3]
Answer Details
(a) \[98\text{ dB}-76\text{ dB}=22\text{ dB}\] The ear defender reduces the sound level by \(22\text{ dB}\). [1]
(b) The wave property mainly reduced is amplitude. [1]
(c) Very loud sound produces large vibrations in the ear. These can damage the hair cells, or sensory cells, in the cochlea. These cells do not repair easily, so the damage can cause hearing loss. [3]
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