Question

1. If the radius r of a circle is measured to be r  0.325 +\- 0.001 m, then calculate the area of the

circle A =3.14 r^2, as well as the uncertainty in the area.

2. Explain the difference between precision and accuracy.

3. Do systematic errors affect precision or accuracy? Do random errors affect precision or accuracy?

Answer 1

accuracy describes the difference between the measurement and the part's actual value, while precision describes the variation you see when you measure the same part repeatedly with the same device.

Systematic errors in experimental observations usually come from the measuring instruments. They may occur because:

• there is something wrong with the instrument or its data handling system, or
• because the instrument is wrongly used by the experimenter.

The accuracy of measurements is often reduced by systematic errors

Random errors in experimental measurements are caused by unknown and unpredictable changes in the experiment. These changes may occur in the measuring instruments or in the environmental conditions.

Examples of causes of random errors are:

• electronic noise in the circuit of an electrical instrument,
• irregular changes in the heat loss rate from a solar collector due to changes in the wind.

systematic errors affect accuracy while random errors affect precision.