Measurment of sound speed in air
Fizikos laboratorinis darbas. Measurement of speed of sound in air by means of Kundt’s method. Work methodics and main formulas. Work results 1 Table. No. 1 frequency 1200Hz. No. 2 Frequency 1400Hz. Nr. 3 Frequency 1600kHz.
APPARATUS: An acoustic apparatus for measurements of the speed of sound in a gas. It consists of: an air-filled horizontal tube 1 with a loudspeaker 2 and a microphone 3 (as sound detector) mounted in- side the tube. There are also a sin-wave oscillator , an oscilloscope , a ruler , and a thermometer .
v – longitudal sound waves speed in air; T – air temperature; γ –molar specific heat difference; R – universal gas constant; M – air molar mass.
1. Turn on sin-wave oscillator and set its electric signal frequen- cy in the range of 1.5–2.5 kHz. Make sure the microphone detects the sound and the oscilloscope shows a sin-wave vol- tage which amplitude is proportional to intensity of the sound wave emitted by the loudspeaker.