Practical 13 - Determination of the speed of sound using stationary waves

Question 1

What’s the method for this practical?

Answer 1

Find an anti node by using a sensor to detect the loudest position for a given frequency
Then, slowly raise the inner tube until we find the next anti node
The distance raised is equal to half a wavelength
Change the frequency and repeat to obtain a set of at least 5 data points

Question 2

What is the distance raised equal to?

Answer 2

Half a wavelength

Question 3

Draw the apparatus for this practical

Answer 3

(See notes)

Question 4

What’s the risk, hazard and control measure for this practical?

Answer 4

Risk - water and electricity
Hazard - damage to equipment
Control measure - clamp tubes securely and be careful

Question 5

Speed of sound equation

Answer 5

c = fλ

Question 6

What is c = f λ the equation for?

Answer 6

The speed of sound

Question 7

What’s our x and y axes for this practical, and what’s the gradient?

Answer 7

X = 1/f
Y = λ
Gradient = speed of sound

Question 8

How do we calculate λ?

Answer 8

Remembering that the distance between 2 antinodes is half a wavelength, so λ = distance between 2 antinodes multiplied by 2

Question 9

Draw the shape of the first harmonic in the tube

Answer 9

(See notes)