A source of constant output power is used to generate a sound which is measured using a sound meter - AQA - A-Level Physics - Question 4 - 2018 - Paper 5
Question 4
A source of constant output power is used to generate a sound which is measured using a sound meter.
The dashed line in Figure 3 shows the intensity level curve ove... show full transcript
Worked Solution & Example Answer:A source of constant output power is used to generate a sound which is measured using a sound meter - AQA - A-Level Physics - Question 4 - 2018 - Paper 5
Step 1
Mention of the 1 kHz being the reference frequency for both scales
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The dBA scale is designed to reflect the sensitivity of human hearing, which peaks around 1 kHz. Therefore, both scales should show a similar response at this frequency.
Step 2
Discuss the response after 5 kHz
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Outside the range of 1 kHz, the ear's sensitivity decreases significantly; therefore, the curve drawn in dBA should drop more steeply after 1 kHz than what is shown in the student's curve.
Step 3
Comment on the maximum value of 4 kHz
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The dBA curve should reach a maximum intensity value at 4 kHz. However, the student's sketch incorrectly assumes that the dBA curve has a similar value, which it does not.
Step 4
Final assessment of the curve
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In conclusion, the student’s dBA curve is partially correct in relation to human hearing sensitivity, but it fails to accurately represent the drop in sensitivity beyond 5 kHz and the maximum intensity at 4 kHz, as per the standard reference curves.
