Stationary Waves On a String

Question 1

What equipment is used in this experiment?

Answer 1

-Signal Generator
-Vibration generator
-Stand
-Pulley
-Wooden Bridge
-100g masses
-Metre rule
-String
-Balance

Question 2

What is the Method?

Answer 2

1.set up the apparatus as shown in the diagram

2. Adjust the length l so that it is 1m, measured using the metre ruler. Increase the frequency f until the string oscillates at the first harmonic.

3.Read and record f.

4.Reduce l by 0.1m and adjust f again until it oscillates at the first harmonic. Measure and record f and repeat this, reducing l by 0.1m each time down to 0.5m.

5. Repeat the experiment twice more and find and record the mean f for each l. Measure the mass of the string on the balance and record it.

Question 3

What graph do you plot and what calculations?

Answer 3

Plot a graph of the mean value of f against 1/l and draw a line of best fit. The wave speed will be two times the gradient. λ = 2l ⇒ v = 2fl = 2f/1/l = 2G where G is the gradient

Question 4

What safety precautions could we consider?

Answer 4

the stand could topple over, so use a counterweight

Question 5

How can this experiment be improved?

Answer 5

-experiment can be repeated with different parameters, different masses to change the tension and different thicknesses to change the mass per unit length

• an oscilloscope can be used to verify the signal generator’s readings.

-signal generator should be left out to stabilise.