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11th grade Sound intensity and the decibel scale worksheet

6 printable versionsChallenge Me10 questions · answer keyFree · no account

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Sound intensity and the decibel scale

Grade 11 Science Worksheet - Challenge Me

NameDate

Circle the best answer, or write your answer on the line.

  1. A sound reads 65 dB. What is its intensity, to 0.01 μW/m², Esme? Use I₀ = 10⁻¹² W/m².

  2. A sound reads 52 dB. What is its intensity, to 0.01 μW/m², Jun? Use I₀ = 10⁻¹² W/m².

  3. A student says an 80 dB sound has twice the intensity of a 40 dB sound. Which reply fits OpenStax, Luz?

    • No; it is 40 times as intense, one per decibel
    • No; it is 10,000 times as intense
    • Yes; twice the decibels means twice the intensity

  4. A student says moving twice as far from a speaker halves the intensity. Which reply fits OpenStax, Milo?

    • Yes; twice as far, half the sound energy per square meter
    • No; it falls to a quarter, as 1 ÷ r²
    • Yes; intensity falls in step with distance

  5. A student says a 0 dB reading means there is no sound energy at all. Which reply fits OpenStax, Noah?

    • Yes; 0 dB means zero intensity
    • No; 0 dB is one unit of intensity, and 10 dB is two units
    • No; 0 dB is 10⁻¹² W/m², the faintest sound heard

  6. A speaker gives 60 dB at 10 m. About what level is it at 1 m, Ren?

    • About 600 dB
    • About 70 dB
    • About 80 dB

  7. A speaker gives 74 dB at 1 m. About what level is it at 2 m, Tala?

    • About 37 dB
    • About 68 dB
    • About 71 dB

  8. Two identical speakers each give 60 dB at a spot. About what level do they give together, Zee?

    • About 63 dB
    • About 60 dB, the same
    • About 120 dB

  9. Ten identical speakers each give 50 dB at a spot. About what level do they give together, Ari?

    • About 53 dB
    • About 60 dB
    • About 500 dB

  10. A spot gets 70 dB from one machine. A second, identical machine also gives 70 dB at that spot. About what is the total, Bo?

    • About 140 dB
    • About 73 dB
    • About 80 dB
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11th grade Sound intensity and the decibel scale worksheet – printable
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About this worksheet

Sound intensity and the decibel scale. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can find intensity as power over area, I = P ÷ (4πr²), and use the inverse square law.
  • I can turn an intensity into decibels with β = 10 log₁₀(I ÷ I₀), and back again, with I₀ = 10⁻¹² W/m².
  • I can use decibel steps: ×10 is +10 dB, ×2 is about +3 dB, twice as far is about −6 dB, and two equal sources add about 3 dB.

Standard: none (IXL parity)

Words to know

intensity: Sound power through each square meter, in W/m²

decibel (dB): A level that counts factors of 10 in intensity

I₀: The threshold of hearing, 10⁻¹² W/m², which is 0 dB

inverse square law: Intensity falls as 1 ÷ r² from a small source

Common mistakes

Your child forgot to square the distance. Sound spreads over a sphere of area 4πr², so I = P ÷ (4πr²).

Your child left out the factor of 10. β = 10 log₁₀(I ÷ I₀), so multiply the logarithm by 10.

Your child left out the reference intensity. I = I₀ × 10^(β ÷ 10), with I₀ = 10⁻¹² W/m².

Questions parents ask

What is the most common mistake with sound intensity and the decibel scale?

Your child forgot to square the distance. Sound spreads over a sphere of area 4πr², so I = P ÷ (4πr²).

Are these 11th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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