Waves, Sound, and Optics
Wave Fundamentals
Core relations
Waves transfer energy and information without transporting matter overall. For many waves, speed, frequency, and wavelength satisfy .
If wave speed stays constant and frequency increases, what happens to wavelength?
From , if is constant and increases, must decrease.
Correct answer: Decreases
What is resonance?
Resonance causes efficient energy transfer and can produce large amplitudes.
Correct answer: A large response when driving frequency matches a natural frequency
Sound and Applications
Sound waves
Sound is a mechanical wave that travels through a medium by compressions and rarefactions. Its speed depends on the medium’s properties, such as stiffness and density.
Practical example
Ultrasound imaging uses high-frequency sound reflections to create images of internal structures.
Sound cannot travel through what medium?
Sound requires a material medium, so it cannot propagate in a vacuum.
Correct answer: Vacuum
Optics and Image Formation
Light as a wave
Light behaves as an electromagnetic wave and also exhibits reflection, refraction, interference, and diffraction. Refraction changes direction because light speed changes in different media.
Optics terms
What causes a lens to form an image?
Lenses bend light by refraction, bringing rays to a focus or spreading them apart.
Correct answer: Refraction
Why are optical fibers useful for communication?
Total internal reflection keeps light confined within the fiber core.
Correct answer: They guide light with low loss over long distances