Fall 2011 Homework 24 Solutions

Fall 2011 Homework 24 Solutions - Physics 21 Fall, 2011...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Physics 21 Fall, 2011 Solution to HW-24 16-33 Two loudspeakers, A and B , are driven by the same amplifier and emit sinusoidal waves in phase. Speaker B is 2.00 m to the right of speaker A . Consider point Q along the extension of the line connecting the speakers, 1.00 m to the right of speaker B . Both speakers emit sound waves that travel directly from the speaker to point Q . (a) What is the lowest frequency for which constructive interference occurs at point Q ? (b) What is the lowest frequency for which destructive interference occurs at point Q ? Speaker A is 3.0 m from Q , and speaker B is 1.0 m from Q , so the path difference is 2.0 m. (a) The speakers are in phase, so for constructive interference, the path difference must be an integral number of wavelengths ( n ). We choose n = 1 to get the lowest frequency, so = 2 . 0 m. Hence f = v f = v = 343 m / s 2 . 0 m = 172 Hz (b) For destructive interference the path difference must be 0.5 wavelengths. [( n + 1 2 ) gives destructive interference, and lowest frequency is from n = 0.] Hence take = 4 . 00 m and f = v = 343 m / s 4 . 0 m = 86 Hz 16-70 Two identical loudspeakers driven by the same am- plifier are located at points A and B , 2.00 m apart. The frequency is 784 Hz and the speed of sound in air is 344...
View Full Document

This note was uploaded on 12/18/2011 for the course PHYS 021 taught by Professor Hickman during the Spring '08 term at Lehigh University .

Page1 / 2

Fall 2011 Homework 24 Solutions - Physics 21 Fall, 2011...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online