MYP Physics · 09 · data analysis
Does ripple speed stay constant?
Waves · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- demanding
- Marks
- 8
- Topics
- 2
- Answer
- Complete
Ripple-tank measurements
The plotted points reproduce the two columns of the question table, in the original units.
Vertical axis (y): Wavelength / cm
Horizontal axis (x): Frequency / Hz
Read the exact data as a table
| Frequency / Hz | Wavelength / cm |
|---|---|
| 5 | 4.8 |
| 6 | 4 |
| 8 | 3 |
| 10 | 2.4 |
| 12 | 2.1 |
These are the supplied values, not a worked answer. No fitted trend is drawn.
A ripple tank has constant water depth. A student changes the source frequency and measures wavelength.
| Frequency / Hz | Wavelength / cm |
|---|---|
| 5.0 | 4.8 |
| 6.0 | 4.0 |
| 8.0 | 3.0 |
| 10.0 | 2.4 |
| 12.0 | 2.1 |
- a
Calculate Calculate the wave speed for the first four rows.
3 marks - b
Evaluate Evaluate the 12.0 Hz result against the constant-speed model.
3 marks - c
Improve Propose one improvement that reduces wavelength-measurement uncertainty.
2 marks
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a
Calculate Calculate the wave speed for the first four rows.
Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.
- 1
Uses v = fλ and converts centimetres to metres.
- 2
Obtains 0.24 m s⁻¹ for the 5.0 Hz and 6.0 Hz rows.
- 3
Obtains 0.24 m s⁻¹ for the 8.0 Hz and 10.0 Hz rows.
b
Evaluate Evaluate the 12.0 Hz result against the constant-speed model.
Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.
- 1
Calculates the 12.0 Hz speed as 12.0 × 0.021 = 0.252 m s⁻¹.
- 2
Compares it with 0.24 m s⁻¹ and identifies a difference of 0.012 m s⁻¹ or 5%.
- 3
Concludes that it is a possible anomalous or uncertain point, but one point alone does not establish a real speed change.
c
Improve Propose one improvement that reduces wavelength-measurement uncertainty.
Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.
- 1
Proposes measuring across several complete wavelengths, using a strobe image, or repeating independent readings.
- 2
Explains that a longer measured distance or repeated mean reduces the percentage uncertainty in one wavelength.
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