Acoustics and Optics Flashcards
7 cards from real Bennett Mechanical Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Acoustics and Optics flashcards as text
The change in pitch as a moving siren passes you is called the:
Answer: Doppler effect
The Doppler effect changes perceived frequency as a sound source moves toward or away.
Total internal reflection in a fiber-optic cable keeps light:
Answer: Trapped inside the fiber
Light striking the fiber wall at a steep angle reflects entirely, staying inside the cable.
When two sound waves combine to produce a louder sound, this is:
Answer: Constructive interference
Constructive interference occurs when waves align in phase, increasing amplitude and loudness.
A camera lens focuses an image onto the sensor by:
Answer: Refracting light to a focal point
The convex camera lens refracts incoming light to converge a sharp image at the sensor.
Which of these has the highest frequency and is inaudible to humans?
Answer: Ultrasound
Ultrasound has frequencies above 20,000 Hz, beyond the range of human hearing.
An air-filled room with hard walls sounds echoey mainly because the walls:
Answer: Reflect sound waves
Hard surfaces reflect rather than absorb sound, causing repeated echoes and reverberation.
The distance between two consecutive crests of a wave is the:
Answer: Wavelength
Wavelength is the distance covered by one complete wave cycle, crest to crest.