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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
data analysis8 marks

A ripple tank has constant water depth. A student changes the source frequency and measures wavelength.

Ripple-tank measurements
Frequency / HzWavelength / cm
5.04.8
6.04.0
8.03.0
10.02.4
12.02.1
  1. a

    Calculate Calculate the wave speed for the first four rows.

    3 marks
  2. b

    Evaluate Evaluate the 12.0 Hz result against the constant-speed model.

    3 marks
  3. c

    Improve Propose one improvement that reduces wavelength-measurement uncertainty.

    2 marks
Ready to self-mark?Reveal the detailed answer guide
Answer overviewKey answer: Uses v = fλ and converts centimetres to metres. Obtains 0.24 m s⁻¹ for the 5.0 Hz and 6.0 Hz rows. Obtains 0.24 m s⁻¹ for the 8.0 Hz and 10.0 Hz rows.
01

a

3 marks

Calculate Calculate the wave speed for the first four rows.

How to approach it

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. 1

    Uses v = fλ and converts centimetres to metres.

  2. 2

    Obtains 0.24 m s⁻¹ for the 5.0 Hz and 6.0 Hz rows.

  3. 3

    Obtains 0.24 m s⁻¹ for the 8.0 Hz and 10.0 Hz rows.

02

b

3 marks

Evaluate Evaluate the 12.0 Hz result against the constant-speed model.

How to approach it

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. 1

    Calculates the 12.0 Hz speed as 12.0 × 0.021 = 0.252 m s⁻¹.

  2. 2

    Compares it with 0.24 m s⁻¹ and identifies a difference of 0.012 m s⁻¹ or 5%.

  3. 3

    Concludes that it is a possible anomalous or uncertain point, but one point alone does not establish a real speed change.

03

c

2 marks

Improve Propose one improvement that reduces wavelength-measurement uncertainty.

How to approach it

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. 1

    Proposes measuring across several complete wavelengths, using a strobe image, or repeating independent readings.

  2. 2

    Explains that a longer measured distance or repeated mean reduces the percentage uncertainty in one wavelength.

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