Question

graded qu... 234:04:02 elapsed which of the following statements is true of vibrations? a) ultrasonic vibrations have a frequency lower than the range for normal hearing. b) neither ultrasonic nor infrasonic vibrations can be...

Explanation:

First, recall the definitions of ultrasonic and infrasonic vibrations. Ultrasonic vibrations have a frequency higher than the upper limit of human hearing (typically above 20,000 Hz), and infrasonic vibrations have a frequency lower than the lower limit of human hearing (typically below 20 Hz).

• Option A: Ultrasonic vibrations have a frequency higher (not lower) than the normal hearing range. So A is false.
• Since the full option B is not visible, but based on the partial text and eliminating A, we assume the correct reasoning (though the full B is needed, but from the given, A is wrong. However, if we consider standard knowledge: Ultrasonic (freq > 20kHz) and infrasonic (freq < 20Hz) are outside human hearing, but they are still vibrations (e.g., ultrasonic is used in imaging, infrasonic in seismic waves). If B's full statement is about them being vibrations (or other correct fact), but since A is wrong, and assuming the options, but the visible part of B starts with "Neither ultrasonic nor infrasonic vibrations can be..." – wait, no, maybe the original question's options (if B is, e.g., "Neither ultrasonic nor infrasonic vibrations are audible to humans" – but the user's image cuts off B. However, based on the given A is wrong (ultrasonic is above hearing range, not below). So if B's full statement is correct (e.g., maybe "Neither ultrasonic nor infrasonic vibrations are in the normal hearing range" or similar), but since the user's image has B partially, but from the given A is incorrect. However, the user's question might have a typo or cut-off, but based on the visible part:

Wait, the user's image shows:

A) Ultrasonic vibrations have a frequency lower than the range for normal hearing. (False, because ultrasonic is higher than 20kHz, normal hearing is 20Hz - 20kHz, so ultrasonic is above, infrasonic is below.)

B) Neither ultrasonic nor infrasonic vibrations can be... (the rest is cut off, but if B is, e.g., "Neither ultrasonic nor infrasonic vibrations are audible to humans" – that's true, because ultrasonic is above 20kHz (human can't hear above 20kHz), infrasonic is below 20Hz (human can't hear below 20Hz). So if B's full statement is about them not being audible (or another correct fact), then B is true. But since A is definitely false, and assuming B's full statement is correct (e.g., "Neither ultrasonic nor infrasonic vibrations are in the audible range for humans" or similar), then B is the correct answer. But since the user's image cuts off B, but from the given A is wrong, so the correct option would be B (assuming the full B is a true statement, like they are not audible or similar).

Answer:

B. Neither ultrasonic nor infrasonic vibrations can be... (assuming the full statement is correct, as A is false because ultrasonic vibrations have a frequency higher than the normal hearing range)