Doorway Diffraction Part A Sound with frequency 1250 Hz leaves a room through a

Question

Doorway Diffraction Part A Sound with frequency 1250 Hz leaves a room through a doorway with a width of 1.15 m At what minimum angle relative to the centerline perpendicular to the doorway will someone outside the room hear no sound? Use 344 m/s for the speed of sound in air and assume that the source and listener are both far enough from the doorway for Fraunhofer diffraction to apply. You can ignore effects of reflections. Express your answer in radians. 47 radians Submit My Answers Give Up Incorrect: Try Again: 2 attempts remaining Provide Feedback Continue

Explanation / Answer

1) Using

= c/f = 344/1250 = 0.2752 m

Now using condition for destructive interference

sin = m/W

= Arcsin(m/W)

if m=1

= Arcsin(0.2752/1.15) = 13.84 degrees

Theta = 13.84degrees

2) width = 2*lambda*D/a

Now a/lambda = 210

Hence width = 2*2/210 = 0.019 m = 19mm

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

---