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11th grade Sound intensity and the decibel scale worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

Level: Building Confidence · On Level · Challenge Me

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Sound intensity and the decibel scale

Grade 11 Science Worksheet - Building Confidence

NameDate

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

  1. A small speaker sends out 0.5 W of sound evenly in all directions. What is the intensity 4 m away, to 0.01 mW/m², Ari?

  2. A small speaker sends out 2 W of sound evenly in all directions. What is the intensity 10 m away, to 0.01 mW/m², Bo?

  3. A small speaker sends out 0.1 W of sound evenly in all directions. What is the intensity 2 m away, to 0.01 mW/m², Kira?

  4. Read this first

    Table, sound levels and intensities (OpenStax Table 17.2), with columns sound, level (dB) and intensity (W/m²)

    Rustle of leaves, 10, 10⁻¹¹; whisper at 1 m, 20, 10⁻¹⁰; quiet home, 30, 10⁻⁹; normal conversation, 60, 10⁻⁶; busy traffic, 70, 10⁻⁵; loud radio, 80, 10⁻⁴.

  5. Using the table, how many times as intense as a quiet home is normal conversation, Luz?

    • 2 times
    • 1000 times
    • 30 times, one per decibel

  6. Using the table, how many times as intense as a whisper at 1 m is busy traffic, Milo?

    • 50 times, one per decibel
    • 100,000 times
    • 3.5 times

  8. On the decibel ruler, a sound drops from 80 dB to 60 dB. What happens to its intensity, Pia?

    • It falls to a hundredth
    • It falls to a half
    • It falls to three quarters

  9. On the decibel ruler, what intensity sits at 30 dB, Ren?

    Use the picture in question 6.

    • 10⁻³⁰ W/m²
    • 10⁻⁹ W/m²
    • 30 × 10⁻¹² W/m²

  10. What does sound intensity measure, by Tala's reading (OpenStax)?

    • The pitch of the sound, in hertz
    • The total power of the source, in watts
    • The sound power passing through each square meter

  11. What does 0 dB mean, by Zee's reading (OpenStax)?

    • A sound too loud to measure
    • Total silence, with zero intensity
    • The faintest sound a person can hear, 10⁻¹² W/m²

  12. A sound meter in a quiet room reads 0 dB. What does that show, Esme?

    • There is no sound energy anywhere in the room
    • The sound is right at the threshold of hearing
    • The meter must be broken, since a room is not that quiet
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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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