Defects of Hearing (AQA A Level Physics): Revision Note
Exam code: 7408
Defects of Hearing
Deterioration of hearing can occur due to
Age
Exposure to excessive and prolonged noise
Genetic factors and disease
Depending on the type of hearing loss, the response is different for different frequencies of sound
Hearing loss due to ageing:
Occurs at all frequencies
With the greatest losses at higher frequencies
Hearing loss due to excessive noise:
Occurs in the frequency range the person was exposed to
With the greatest loss at 4 kHz
Hearing Loss & Frequency Variation
Depending on the type of hearing loss, different responses to frequencies of sound are found to deteriorate
The degree of hearing loss can be tested by obtaining equal loudness curves and comparing the results with the curves for normal hearing
The same, but inverted, curve can be obtained using the dBA scale
Comparing Hearing Defects
Curve A shows the response for a young person with no hearing loss. Curve B shows the response for an older person with hearing loss due to ageing. Curve C shows the response for a young person with hearing damage due to excessive noise
Worked Example
A hearing test was used to obtain threshold hearing audiograms for a group of people. The diagram below shows the audiogram obtained for a person with normal hearing.
On the graph, sketch curves to show:
(a) a curve labelled X to show a person suffering from hearing loss due to excessive noise
(b) a curve labelled Y to show a person suffering from hearing loss due to old age.
Answer:
Part (a)
Hearing loss due to excessive noise:
Curve X: hearing loss increases up to 4 kHz then decreases after this frequency
Part (b)
Hearing loss due to ageing:
Curve Y: loss increases as frequency increases
Unlock more, it's free!
Join the 100,000+ Students that ❤️ Save My Exams
the (exam) results speak for themselves:
Was this revision note helpful?
Build on this topic
