Question

although a door is only slightly opened, sound will pass from one room to another due mainly to:
select one:
reflection.
refraction.
diffraction.
absorption.

a piano plays the note a at a frequency of 440 hertz. what is the approximate wavelength in meters of this sound wave if the speed of sound in air is 340 meters per second?
select one:
0.007 meters
0.077 meters
0.77 meters
7.7 meters

Explanation:

First Question

Sound passing through a slightly open door is due to diffraction. Diffraction is the bending of waves around obstacles or through openings. Reflection is bouncing back of waves, refraction is bending when entering a different medium, and absorption is waves being taken in by a material.

Step1: Recall the formula for wave speed

The formula is \(v = f\lambda\), where \(v\) is speed, \(f\) is frequency, and \(\lambda\) is wavelength.

Step2: Solve for wavelength \(\lambda\)

Rearrange the formula to \(\lambda=\frac{v}{f}\). Substitute \(v = 340\ m/s\) and \(f=440\ Hz\). So \(\lambda=\frac{340}{440}\approx0.77\ m\)

Answer:

C. diffraction

Second Question