NCIDQ IDFX Practice Exam

What's a common characteristic of materials with a coefficient below 0.2?

1. They are sound absorbing

2. They are sound reflecting

3. They contribute to noise reduction

4. They dissipate sound energy

The correct answer is: They are sound reflecting

Materials with a coefficient below 0.2 are typically sound reflecting. This classification indicates that these materials reflect a significant amount of sound energy rather than absorbing it. The coefficient is a measure of the material’s ability to absorb sound; thus, a low coefficient implies that the material is not effective at absorbing sound waves. In contexts such as interior design, understanding sound reflection is essential when selecting materials for spaces that require clarity and audibility, like auditoriums or conference rooms. High sound reflection can help maintain auditory presence and ensure that voices or sounds can carry across distances effectively. Sound-absorbing materials, which have higher coefficients generally above 0.2, would be used specifically to improve acoustics by reducing echoes and background noise. Options concerning noise reduction and dissipation of sound energy also pertain to materials that typically have a higher absorption coefficient, allowing them to convert sound energy into heat rather than reflecting it.