1.1. State which two measurements a micrometer screw gauge would be used to measure:

• The diameter of a thin wire (wire gauge)

• The length of a pencil

• The thickness of a sheet of paper

• The thickness of a water pipe

1.2. A student records 5 repeat readings using a micrometer screw gauge in mm shown in Table 1.

Table 1

Calculate the average of the readings in Table 1. Give your answer to an appropriate number of significant figures.

1.3. Give two reasons why taking repeat readings provides more accurate data.

1.4. Another student repeats the same experiment using a micrometer screw gauge and obtains an average value of 1.53 ± 0.03 mm.

Calculate the percentage uncertainty in this student’s average to the appropriate number of significant figures.