Environmental Science: Numerical Questions – Noise Addition of Noise

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1. A person is exposed to two sound levels of 80 dB and 100 dB simultaneously. What is the average noise level the person experiences?

  1. ~97 dB
  2. ~87 dB
  3. ~90 dB
  4. ~93 dB

Explanation:

Difference and Added to Higher Sound Value
Difference (L2-L1)Added to Higher Sound Value
03
12.5
22.1
31.5
41.5
51
61
70.8
80.6
90.5
100.4
Difference and Added to Higher Sound Value
Difference (L2-L1)Added to Higher Sound Value
0 or 13
2 or 32
4 to 81
9 or more0

2. On take - off, an aeroplane generates noise level of 120 db. If 5 such aeroplanes take – off simultaneously what will be the noise level?

  1. ~126.98 dB
  2. ~124.98 dB
  3. ~123.86 dB
  4. ~122.98 dB

Answer: (A) ~126.98 dB

Explanation: L_eq = L_i + 10 Log (n)

L_eq = 120 + 10 Log (5)

L_eq = 120 + 10 ∗ 0.69

L_eq = 120 + 6.9

L_eq = 126.9

3. The resultant of two noise levels of 50 dB and 55 dB is:

  1. 58 dB
  2. 55.41 dB
  3. 52.5 dB
  4. 56.19 dB

Answer: Option (D) 56.19 dB

Explanation:

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