Question

1. The figure to the right shows a particle undergoing simple harmonic motion described by x(t)= A cos(at +o). Notice that x(0) = A/2. What is the phase constant? 

2. The figure to the right shows a snapshot of circular waves emitted by two in- phase sources. The point marked by the dot (directly in between two wave fronts emitted from source I at the time shown) is a point of: 

 A. Maximum constructive interference.

 B. Maximum destructive interference.

 C. Partially constructive interference.

 D. Partially destructive interference.

 E. No interference.

 F. Cannot say without knowing the type of wave. 

3. The displacement graph of air molecules shown to the right could represent a standing sound wave in a tube with: 

 A. Two closed ends.

 B. An open end on the right, and a closed end on the left.

 C. A closed end on the right, and an open end on the left.

 D. Two open ends.

 E. The depicted displacement graph cannot represent a standing wave.

 4. On the decibel scale, is it possible to have an intensity of-10 dB? If so, what would it mean?

 A No; intensity on the decibel scale must always be greater than 0.

 B. No; intensity on the decibel scale must always be greater than or equal to 0.

 C. Yes; it means it is below the threshold of human hearing.

 D. Yes; it means the intensity of the sound, I, is negative.

 E. Yes; it means the amplitude of the sound wave is negative.

Answer 1

Answer 2