11. Which of the following materials is the best absorber of sound waves?
a) Glass
b) Rubber
c) Metal
d) Foam
Answer: d) Foam
12. The unit decibel (dB) is used to measure:
a) Frequency
b) Amplitude
c) Wavelength
d) Speed
Answer: b) Amplitude
13. Which of the following is not a characteristic of a sound wave?
a) Reflection
b) Refraction
c) Diffraction
d) Absorption
Answer: b) Refraction
14. Sound waves cannot travel through:
a) Vacuum
b) Air
c) Water
d) Solids
Answer: a) Vacuum
15. The phenomenon of sound waves bouncing off a surface is known as:
a) Reflection
b) Refraction
c) Diffraction
d) Absorption
Answer: a) Reflection
