# Audio Engineering MCQ Questions and Answers – Reflection and Diffraction of Sound Waves

This set of Audio Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Reflection and Diffraction of Sound Waves”.

1. What is termed as the amount of sound energy that is reflected off a surface?
a) Reflection
b) Refraction
c) Diffraction
d) Frequency

Explanation: The amount of sound energy that is reflected off a surface is termed as reflection. Hard and non-porous surface reflects more sound than soft porous surface. Sound reflection can enhance the quality of the sound.

2. What causes reverberation?
a) Diffraction
b) Frequency
c) Reflection
d) Refraction

Explanation: Reflection causes reverberation (the collection of reflected sounds from the surfaces like furniture, air etc. in an enclosure like an auditorium). Some sound reflection can enhance the quality of the sound.

3. What can occur when the speed of a wave changes, as it moves from one environment to another?
a) Reflection
b) Diffraction
c) Frequency
d) Refraction

Explanation: Sound waves can also be refracted. Refraction can occur when the speed of a wave changes, as it moves from one environment (medium) to another. When a wave enters a new environment, the change in speed will also change its wavelength.

4. After refraction, the wave has the same speed, wavelength and direction but different frequency.
a) True
b) False

Explanation: The above statement is false. Sound waves can also be refracted. After refraction, the wave has the same frequency but different speed, wavelength and direction. Change in speed will also change the wavelength when a wave enters a new environment.

5. What is caused by bending across obstacles in sound waves?
a) Diffraction
b) Reflection
c) Frequency
d) Refraction

Explanation: Diffraction causes bending across obstacles. The bending of waves around small obstacles and the spreading out of waves is called diffraction. As the wavelength of sound is much larger than that of the light, bending is quite obvious around small obstacles like casing of a microphone or a loudspeaker.
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6. Which audio frequencies have smaller wavelength and suffer less diffraction?
a) Low
b) High
c) Medium
d) Low and High

Explanation: High audio frequencies have smaller wavelength and therefore suffer less diffraction, resulting in Shadows. Low audio frequencies, being of larger wavelength, do not cause Shadows and pass easily around obstacles.

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