Wave Basics
Which wave must travel through matter?
A. Light wave
B. Sound wave
C. Radio wave
D. X-ray
Answer: B. Sound wave
Explanation: Sound is a mechanical wave, so it needs a medium such as a solid, liquid, or gas.
What is the main job of a wave-energy converter?
A. Turn wave energy into electrical energy
B. Stop all waves
C. Create matter
D. Change electricity into color
Answer: A. Turn wave energy into electrical energy
Explanation: A wave-energy converter captures wave motion and uses it to generate electricity.
Light strikes a mirror and bounces back. Which wave behavior occurs?
A. Absorption
B. Reflection
C. Transmission
D. Refraction
Answer: B. Reflection
Explanation: Reflection occurs when a wave bounces off a surface.
Which property of a sound wave determines its loudness?
A. Amplitude
B. Frequency
C. Color
D. Refraction
Answer: A. Amplitude
Explanation: Greater amplitude means greater intensity and a louder sound.
What happens during resonance?
A. An object vibrates strongly at its natural frequency.
B. All vibrations stop.
C. Light changes into matter.
D. Sound travels through a vacuum.
Answer: A. An object vibrates strongly at its natural frequency.
Explanation: Resonance occurs when a vibration matches an object’s natural frequency and produces a larger response.
Two waves have the same frequency. Wave X has a greater amplitude. What does Wave X carry?
A. Less energy
B. More energy
C. No energy
D. A longer period only
Answer: B. More energy
Explanation: A wave with greater amplitude transfers more energy.
In a wave-energy device, an ocean buoy moves up and down. What energy change occurs in the generator?
A. Mechanical energy to electrical energy
B. Electrical energy to chemical energy
C. Light energy to sound energy
D. Thermal energy to nuclear energy
Answer: A. Mechanical energy to electrical energy
Explanation: The mechanical motion of the buoy turns a generator that produces electrical energy.
A pillow placed in front of a speaker makes the sound quieter. Which wave behavior is demonstrated?
A. Absorption
B. Reflection
C. Transmission
D. Resonance
Answer: A. Absorption
Explanation: The pillow absorbs some of the sound energy, so less sound continues through the air.
Which property of a sound wave determines its pitch?
A. Amplitude
B. Frequency
C. Brightness
D. Reflection
Answer: B. Frequency
Explanation: Higher frequency produces a higher pitch. Lower frequency produces a lower pitch.
Which action best demonstrates resonance on a playground swing?
A. Pushing the swing using the correct repeated timing
B. Holding the swing still
C. Pushing once in the wrong direction
D. Removing the seat
Answer: A. Pushing the swing using the correct repeated timing
Explanation: Timed pushes match the swing’s natural motion and increase its amplitude.
Wave A has a higher frequency than Wave B. If both waves travel at the same speed, what is true?
A. Wave A has a longer wavelength.
B. Wave A has a shorter wavelength.
C. Wave A has no wavelength.
D. Their wavelengths must be equal.
Answer: B. Wave A has a shorter wavelength.
Explanation: At the same speed, frequency and wavelength have an inverse relationship. As frequency increases, wavelength decreases.
Which water wave would usually allow a converter to capture the most energy?
A. A wave with a small amplitude
B. A wave with a large amplitude
C. A wave with zero amplitude
D. A wave that does not move
Answer: B. A wave with a large amplitude
Explanation: A wave with a larger amplitude carries more energy that can be captured.
Light passes through a clear window. Which wave behavior is demonstrated?
A. Reflection only
B. Absorption only
C. Transmission
D. Resonance
Answer: C. Transmission
Explanation: Transmission occurs when a wave passes through a material.
A student tests how the length of a ruler hanging over a desk affects pitch. What should the student keep the same?
A. The ruler used
B. The length hanging over the desk
C. The measured pitch
D. The conclusion
Answer: A. The ruler used
Explanation: In a controlled investigation, the student changes one variable while keeping other conditions the same.
One tuning fork causes an identical nearby tuning fork to begin vibrating. Why?
A. They have matching natural frequencies.
B. The second fork absorbs all the sound.
C. Light refracts between them.
D. Their colors are the same.
Answer: A. They have matching natural frequencies.
Explanation: The sound from the first tuning fork causes the second fork to vibrate at its natural frequency.
The amplitude of a light wave increases. What change would most likely be observed?
A. The light looks brighter.
B. The light needs a medium.
C. The color must become red.
D. The speed becomes zero.
Answer: A. The light looks brighter.
Explanation: Greater light-wave amplitude means greater intensity, which is usually seen as greater brightness.
A wave-energy device makes more electricity when waves hit it more often. Which wave property increased?
A. Frequency
B. Color
C. Reflection
D. Medium size
Answer: A. Frequency
Explanation: Frequency describes how many waves or cycles occur during a certain amount of time.
A straw looks bent where it enters water. Which wave behavior causes this observation?
A. Refraction
B. Resonance
C. Absorption
D. Vibration
Answer: A. Refraction
Explanation: Refraction is the bending or change in direction of a wave because its speed changes when it enters a different material.
Tone X has a frequency of 200 Hz. Tone Y has a frequency of 400 Hz. Which tone has the higher pitch?
A. Tone X
B. Tone Y
C. They have the same pitch.
D. Pitch cannot be compared.
Answer: B. Tone Y
Explanation: Tone Y has the greater frequency, so it produces the higher pitch.
A guitar player shortens the vibrating part of a string. What change occurs?
A. Frequency and pitch increase.
B. Frequency and pitch decrease.
C. Amplitude must become zero.
D. Sound no longer needs matter.
Answer: A. Frequency and pitch increase.
Explanation: A shorter vibrating string has a higher natural frequency and produces a higher pitch.
Which statement best explains how waves transfer energy?
A. Matter moves permanently with the wave.
B. Energy moves while matter mainly vibrates in place.
C. Waves create new matter.
D. Only light waves transfer energy.
Answer: B. Energy moves while matter mainly vibrates in place.
Explanation: Waves transfer energy from place to place without permanently moving matter from one location to another.
A student tests wave height and electrical output. Which result best supports the design of a wave-energy converter?
A. Electrical output decreases as wave height increases.
B. Electrical output increases as wave height increases.
C. Electrical output is always zero.
D. Wave height is never measured.
Answer: B. Electrical output increases as wave height increases.
Explanation: This result provides evidence that greater-amplitude waves provide more usable energy.
Why does a prism separate white light into different colors?
A. Every color is absorbed.
B. Different wavelengths refract by different amounts.
C. Sound reflects inside the prism.
D. The prism creates new colors.
Answer: B. Different wavelengths refract by different amounts.
Explanation: White light contains many wavelengths. The prism bends each wavelength by a different amount.
A sound wave’s amplitude increases, but its frequency stays the same. What happens to the sound?
A. It becomes louder, but the pitch stays the same.
B. It becomes quieter and has a higher pitch.
C. Its loudness stays the same, but its pitch decreases.
D. The sound can no longer travel.
Answer: A. It becomes louder, but the pitch stays the same.
Explanation: Amplitude affects loudness. Frequency affects pitch.
Why does the hollow body of an acoustic guitar make the sound easier to hear?
A. It resonates and transfers more vibration to the air.
B. It absorbs every sound wave.
C. It removes the string’s frequency.
D. It turns sound into visible light.
Answer: A. It resonates and transfers more vibration to the air.
Explanation: The guitar body and the air inside it vibrate with the strings, increasing the sound’s intensity.