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CAIE A-Level Physics AS 1.3 Errors and Uncertainties Questions

Practise distinguishing error types, judging precision and accuracy, and propagating measurement uncertainty.

Syllabus
2028–2030
Course
Physics 9702
Level
AS

Covered syllabus points

1.3.1—The effects of systematic errors (including zero errors) and random errors1.3.2—The distinction between precision and accuracy1.3.3—Assess the uncertainty in a derived quantity by simple addition of absolute

Question 1

[Maximum number: 1]

The measurement of a physical quantity may be subject to random errors and to systematic errors.

Which statement is correct?

A

A systematic error cannot be reduced by adjusting the apparatus.

B

A systematic error results in a different reading each time the measurement is taken.

C

Random errors are always caused by the person taking the measurement.

D

Random errors can be reduced by taking the average of several measurements.

Question 2

[Maximum number: 1]

A desk has a true width of 50.0 cm .
Two students, X and Y, measure the width of the desk.
Student X uses a tape measure and records a width of (49.5±0.5)cm(49.5 \pm 0.5) \mathrm{cm}.
Student Y uses a metre rule and records a width of (51.4±0.1)cm(51.4 \pm 0.1) \mathrm{cm}.
Which statement about the measurement of student X is correct?

A

It is less accurate and less precise than the measurement of student Y .

B

It is less accurate but more precise than the measurement of student Y .

C

It is more accurate and more precise than the measurement of student Y .

D

It is more accurate but less precise than the measurement of student Y .

Question 3

[Maximum number: 1]

The Young modulus of the material of a wire is to be found. The Young modulus E is given by the equation shown.

E=4FLπd2xE=\frac{4 F L}{\pi d^{2} x}

The wire is extended by a known force and the following measurements are made.
Which measurement has the largest effect on the uncertainty in the value of the calculated Young modulus?

measurement

symbol

value

length of wire before force applied

L

2.043±0.002 m2.043 \pm 0.002 \mathrm{~m}

diameter of wire

d

0.54±0.02 mm0.54 \pm 0.02 \mathrm{~mm}

force applied

F

19.62±0.01 N19.62 \pm 0.01 \mathrm{~N}

extension of wire with force applied

x

5.2±0.2 mm5.2 \pm 0.2 \mathrm{~mm}

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