SAT Subject Physics Practice Question 423: Answer and Explanation
14. Some opera singers are able to use their voice to shatter a crystal glass. They can do this because of
A. acoustic reflection.
B. multiple echoes.
Correct Answer: D
The correct answer is (D). If the input frequency of a wave system is equal to its vibrating frequency, the resonant system acts to amplify the waves, thus transferring their energy into the delicate crystal and breaking it.