Physics Review Question

Unit: waves
Year: 1995 Question#: 44
Question: When an opera singer hits a high-pitch note, a glass on the opposite side of the opera hall shatters. Which statement best explains this phenomenon?

(1 ) The frequency of the note and natural vibration frequency of the glass are equal.
(2 ) The vibrations of the note are polarized by the shape of the opera hall.
(3 ) The amplitude of the note increases before it reaches the glass.
(4 ) the singer and glass are separated by an integral number of wavelengths.

What is this question really asking?




Explanation by: Ajemo H

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Answer 1
The frequency of the note and natural vibration frequency of the glass are equal.

CORRECT

The only way for the glass to break is if the singers note was at the same frequency as the natural frequency of the glass. Other notes might move the glass a little, but putting energy in at the obejects natural frequency causes resonance. The vibrations continue to build in the glass until it bends beyond its breaking point and shatters.

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Answer 2
The vibrations of the note are polarized by the shape of the opera hall.

INCORRECT

You can not polarize a longitudinal wave. Only transverse waves can be polarized. return to top



























Answer 3
The amplitude of the note increases before it reaches the glass.

INCORRECT

The amplitude of the note (volume) would not increase on its own. The glass cannot continue to be pushed unless the note's and the glass's natural frequency are the same. return to top


























Answer 4
the singer and glass are separated by an integral number of wavelengths.

INCORRECT

The number of wave lengths away the opera singer was from the glass has no importance. return to top


























What's this question really asking?

This question is asking if you know the concept of the transfer of energy through waves and resonance. return to top

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