Required Practical 1 - Stationary Waves on string

What equipment is needed for investigating the variation of frequency of stationary waves on a string with length, tension, and mass per unit length?

Signal generator, vibration generator, stand, pulley, wooden bridge, 100g masses with holder, metre ruler, 1.5m long string, balance.

How do you set up the apparatus for investigating stationary waves on a string?

Set up the apparatus with the string passing over a pulley and a wooden bridge. Attach the string to the vibration generator and hang masses from the string.

How many times should you repeat the measurements, and why?

Repeat the experiment twice more to find and record the mean frequency for each length, ensuring more accurate and reliable data.

How do you measure the frequency and length in the stationary waves experiment?

Adjust the length to 1.000m, increase the frequency until the first harmonic is observed, and record the frequency. Repeat for decreasing lengths by 0.100m down to 0.500m and record the frequencies.

How do you calculate the wave speed from the graph?

Plot the mean frequency against 1/length and draw a line of best fit. The wave speed (v) is two times the gradient of this graph.

What formula relates the wave speed to the string length and frequency?

The wave speed v can be calculated using λ=2l and v=fλ, so v=2f x gradient

How do you determine the tension and mass per unit length of the string?

The tension is the weight of the hanging mass (e.g., 100g gives 0.981N). The mass per unit length is the mass of the string divided by its length (1.5m).

What is another formula for the wave speed, and how does it compare with the graph method?

The wave speed can also be calculated using v=Root(T/μ) where T is tension and μ is mass per unit length. This value can be compared with the value obtained from the graph.

What safety precautions should be taken during the experiment?

Ensure the stand is stable to prevent it from toppling over. Use a counterweight if necessary.

How can the experiment be improved?

Repeat with different masses to change tension and with different thicknesses of string to change mass per unit length. Use an oscilloscope to verify the signal generator's readings. Allow the signal generator to stabilize for about 20 minutes.