Lesson: Loudness Physics • 9th Grade

In this lesson, we will learn how to relate the loudness of sounds in decibels to the intensity of soundwaves.

Lesson Worksheet

Q1:

The sound of a vacuum cleaner has an intensity at the position of the ear of the person using the cleaner of 17.5 µW/m². What is the loudness of the sound?

Q2:

The intensity of a sound wave is related to the velocity of the sound wave and the pressure at a point in the medium that the sound wave moves through.

Would an increase in the velocity of a sound wave increase or decrease the intensity of the sound wave?

Would an increase in the pressure at a point in the medium that the sound wave moves through increase or decrease the intensity of the sound wave?

Q3:

The intensity of a sound wave is the average power in the wave per unit area that the wave is incident on. Which of the following is the base SI unit that corresponds to the ratio of power to area?