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Edexcel A-Level Physics Handling Data

Review handling data in Edexcel A-Level Physics through repeated measurements, significant figures, mean values and combined measurement uncertainty.

Syllabus
Pearson Edexcel International Advanced Subsidiary/Advanced Level
Course
Physics XPH11/YPH11
Level
AS

Exam points

  • calculate means from repeated readings, then round values to the precision shown by the raw data
  • combine absolute and percentage uncertainties when measurements are subtracted, multiplied or powered
  • assess the largest source of uncertainty before comparing calculated ranges with physical conclusions

Covered syllabus points

C.1.1—Significant figuresC.1.2—Arithmetic meansC.1.3—Simple probabilityC.1.4—Order-of-magnitude calculationsC.1.5—Combined measurement uncertainty

C.1 Handling data question 1

[Maximum number: 2]

A student used a laser and screen to determine the diameter of a hair. The apparatus was arranged as shown.

Figure for Question C.1 Handling data question 1 — Edexcel A-Level Physics AS

The student repeated the procedure using three different lasers. Each laser produced a different wavelength of light.

The student calculated the diameter d of the hair using each laser. He recorded the values as shown.

Table for Question C.1 Handling data question 1 — Edexcel A-Level Physics AS

Determine the mean value of d.

Mean value of d=

C.1 Handling data question 2

[Maximum number: 2]

A student carried out an experiment to compare the speed of sound in air and the speed of sound in wood. The student used a long piece of wood, a hammer and two microphones, as shown.

Figure for Question C.1 Handling data question 2 — Edexcel A-Level Physics AS

The microphones were connected to a 2-beam oscilloscope. The student hit the wood with a metal hammer producing a sharp sound that travelled through the air. The oscilloscope traces produced by the microphones and the time per division dial are shown.

Figure for Question C.1 Handling data question 2 — Edexcel A-Level Physics AS
Figure for Question C.1 Handling data question 2 — Edexcel A-Level Physics AS

The student was given the following equation and data to find a value for the speed of sound in oak.

v = √(E/ρ)

Young modulus E of oak = 11.2 GPa ± 0.5 GPa
Density ρ of oak = 650 kg m^-3 with an uncertainty of 3%

Assess which of these values was the more significant source of uncertainty in the value of the speed of sound.

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