24.3 (i) Describe how each type of measurement was taken.
(ii) How was it known that the air column was vibrating at its first harmonic? (iii) Using all of the data, calculate the speed of sound in air. (iv) State one potential source of error in this experiment.
Q2 A student investigated the variation of the fundamental frequency f of a stretched string with its length l. The table shows the data recorded by the student. Table 11.7
f / Hz 256 l / cm 49.2
288 45.1
320 40.9
384 426.6 480 33.2
30.1 26.5
512 25.1
Draw a labelled diagram of the apparatus used in this experiment. Indicate on the diagram: (i) the points between which the length of the wire was measured (ii) how the student set the string vibrating
(iii) how the student knew that the string was vibrating at its fundamental frequency.
Plot a suitable graph on graph paper to show the relationship between fundamental frequency and length for the stretched string.
What does the graph tell us about the relationship between fundamental frequency and length of a stretched string?
Q3 A student obtained the following data during an investigation of the variation of the fundamental frequency f of a stretched string with its tension T. The length of the string was kept constant.
The table shows the data recorded by the student. Table 11.8
T / N 144.0 207.4 282.2 368.6 466.6 576.0 679.0 f / Hz
250 300 350 400 450 500 550 (i) Describe with the aid of a diagram how the student obtained this data.
(ii) Plot a suitable graph on graph paper to show the relationship between fundamental frequency and tension for the stretched string.
(iii) State this relationship and explain how your graph verifies it. (iv) Use any data pair from the table to calculate the mass per unit length of the string. (12)
