Bennett Mechanical Test Acoustics and Optics 3 — Questions and Answers
Question 1: Why can't sound travel through outer space?
- There is no medium to carry it (Correct answer)
- Space is too cold
- Light blocks it
- There is no gravity
Correct answer: There is no medium to carry it
Sound needs a material medium to vibrate through, and space is a near vacuum.
Question 2: A concave (diverging) lens causes parallel light rays to:
- Spread apart (Correct answer)
- Converge to a point
- Stop completely
- Reflect backward
Correct answer: Spread apart
A concave lens diverges parallel rays, making objects appear smaller.
Question 3: The pitch of a guitar string rises when the string is made:
- Shorter and tighter (Correct answer)
- Longer and looser
- Thicker
- Heavier
Correct answer: Shorter and tighter
Shorter, tighter strings vibrate at higher frequencies, producing a higher pitch.
Question 4: White light passing through a prism separates into colors because each color:
- Bends by a different amount (Correct answer)
- Travels at the same speed
- Has the same wavelength
- Reflects equally
Correct answer: Bends by a different amount
Different wavelengths refract by different amounts, spreading white light into a spectrum.
Question 5: A material that absorbs sound well, like foam, is used to:
- Reduce echoes (Correct answer)
- Amplify sound
- Increase pitch
- Reflect light
Correct answer: Reduce echoes
Soft, porous materials absorb sound energy and cut down reflections and echoes.
Question 6: The bending of light around the edge of an obstacle is called:
- Diffraction (Correct answer)
- Reflection
- Absorption
- Refraction
Correct answer: Diffraction
Diffraction is the spreading of waves as they pass an edge or through a gap.
Question 7: Which color of visible light has the longest wavelength?
- Red (Correct answer)
- Blue
- Violet
- Green
Correct answer: Red
Red light has the longest wavelength and lowest frequency in the visible spectrum.
Bennett Mechanical Test Acoustics and Optics 3
Why can't sound travel through outer space?