Physics Experiment 1

Student Name: Mohamed Ashraf Khaled ID: 109624

Speed of sound in air

Objective:To estimate the speed of sound in air by using kundt`s tube.

Tools: Kundt’s tubeFunction generatorOscilloscope Microphone probe rod

Movable piston

Theory:kundt`s tube is transparent horizontal pipe. At the ends there is a source of sound producing a single frequency sound wave and the other end of the pipe is blocked by a moveable piston which can be used to adjust the length of the pipe at the end of the movable piston there is a microphone probe rod.

After the sound generator is turned on, at this time a standing waves are formed. The oscilloscope began to read the waves which shows the nodes and the antinodes so we can calculate the λ (wave length) from it as the distance between the nodes and the antinodes is λ/2.

Then the frequency is known so we can apply the law "C = λ.υ". So the "C" speed of sound is determined. We can also get the speed of sound in any other medium used by this

experiment.Procedure: 1.Set up the apparatus as shown below.

2. Switch on the signal generator and slowly increase the frequency until theOscilloscope will show the nodes and antinodes.3. Identify the position of the nodes and antinodes of the stationary wave.Hence find the wavelength of the sound wave.4. Record the resonant frequency from the signal generator and calculate theSpeed of sound in air.5. Repeat the experiment several times by increasing the frequency to the other resonant modes.

Results:

L1 L2 ∆L F (Hz)(×103)

1/f (sec)(×10-3)

18.1 35.5 17.4 1 112.1 24.3 12.2 1.4 0.719.3 19.1 9.8 1.8 0.5614.6 28.9 14.3 1.2 0.838.1 17.1 9 2.0 0.56.7 15.1 8.4 2.2 0.45

Errors estimation:1. The speed of sound depends on the temperature and as the temperature

in the lab is lower than normal temperature so the speed of sound isn`t 100% accurate.

2. The error happens due to the human mistakes in reading and calculating the values.

3. The errors of the equipments used like oscilloscope, microphone, etc.

Conclusion:

1. The speed of sound depends on both the frequency and the wave length and by determining both of them we can calculate the speed of sound at any medium.

2. The sound wave consists of parts which called nodes and antinodes and these parts are used to calculate the wave length as wave length is the distance between two non successive nodes or antinodes.

3. The sound wave consists of many regions where at some regions there is a high sound and at another region no sound is formed.

4. The speed of sound can differs from one medium to another.