Uncertainties

A digital caliper is used to measure the 28.50 mm width of a plastic ruler. The digital caliper reads to the nearest 0.01 mm.

What is the correct way to record this reading?

• 0.02850 ± 0.01 m

• 0.0285 ± 0.001 m

• (2.850 ± 0.001) × 10^-2 m

• (2.850 ± 0.001) × 10^-3 m

The first length measured in a laboratory experiment is 2.5 + 0.1 m and the second length 3.4 + 0.1 m. What is the uncertainty of the difference in the lengths?

• 0.1 m

• 0.2 m

• 0.3 m

• 0.4 m

The first length measured in a laboratory experiment is 2.5 + 0.1 m and the second length 3.4 + 0.1 m. What is the uncertainty of the sum of the lengths?

• 0.1 m

• 0.2 m

• 0.3 m

• 0.4 m

• 2.5 %

• 3.0 %

• 7.0 %

• 10.0 %

• 2 %

• 3 %

• 5 %

• 6 %

A thermometer can be read to an accuracy of ±0.5 °C. This thermometer is used to measure a temperature rise from 40 °C to 100 °C.

What is the percentage uncertainty in the measurement of the temperature rise?

• 0.5 %

• 0.8 %

• 1.3 %

• 1.7 %

• 1.1 %

• 1.8 %

• 2.5 %

• 3.0 %