F2 01.3 Relative Errors and Percentage Errors

David estimates the number of balls in a box as 60. If the actual number of balls is 75, find the relative error of David’s estimation.

• 1.25

• 0.8

• 0.25

• 0.2

The measured length of a ribbon is 68 cm, correct to the nearest cm. Find the relative error.

The weight of a notebook computer is (3.0 ± 0.15) kg. Find the relative error of this measurement.

• 0.2

• 0.1

• 0.05

• 0.025

Ken uses a ruler with scale interval of 0.5 cm to measure the length of each side of a square. If the length of each side is measured as 12.5 cm, find the relative error in calculating the perimeter of the square.

• 0.02

• 0.04

• 0.08

• None of the above.

A cup of water measures 800 mL (corr. to the nearest 5 mL). Find the percentage error of the measurement.

• 0.3125%

• 0.625%

• 3.125%

• 6.25%

The weight of an object is 4.0 g, correct to 2 significant figures. Find the percentage error.

• 0.0125%

• 0.05%

• 1.25%

• 5%

• 1.5 years

• 2.5 years

• 5 years

• 42.0 ≤ x < 46.0

• 43.0 ≤ x < 45.0

• 43.6 ≤ x < 44.4

• 43.8 ≤ x < 44.2

• 2.5

• 5

• 10

• 15

The distance travelled by an insect is 2 000 mm, correct to n significant figure(s). If the percentage error is 0.25%, find n.

• 1

• 2

• 3

• 4