A-LEVEL Physics: 1.1.5: Uncertainty (Seneca)

Question 1

What is ‘Uncertainty’?

Answer 1

Uncertainty is a Measure of the Confidence of a Measurement. It shows the Range of Values that the True Value lies in.

Question 2

What is ‘Absolute Uncertainty’?

Answer 2

Absolute Uncertainty is the Range of Possible Real Values.

eg +_0.5mm

Question 3

What is ‘Fractional Uncertainty’?

Answer 3

Fractional Uncertainty is the Absolute Uncertainty Divided by the Measured Value.
Given as a Fraction.

Question 4

What is ‘Percentage Uncertainty’?

Answer 4

Percentage Uncertainty is the Fractional Uncertainty of a Measurement given as a Percentage.

Question 5

How do you Plot Uncertainties on Graphs?

Answer 5

With Error Bars.

Question 6

What do you Use to Plot Uncertainties on Graphs?

Answer 6

Error Bars.

Question 7

How can you Find Errors on a Graph?

Answer 7

A Systematic Error can be Spotted on a Graph if the Theory & the Results Do Not Match for when the Independent Variable is 0.

Eg when Measuring the Current in a Circuit, we would expect the Current to be 0 when the Supply P.D. is . So when it isn’t, we know that there is a Systematic Error.