Question

a good- quality measuring tape can be of by 0.53 over a distance of 21 cm.... What is the percent uncertainty?

Answer 1

Given length of the measuring tape = 21 cm

Length by which it can be off ( error) = 0.53 cm .

Uncertainty is the maximum value by which a measurement can differ from its original value .

In this case Uncertainty is 0.53 cm , because it is the maximum value which can be observed different from original value of 21 cm .

Percentage uncertainty = (uncertainty/ original value)×100

Substituting the given values in the above formula we get

Percentage uncertainty =.(0.53/21)× 100

= (53/21)

=2.52

Therefore percentage uncertainty in the given measuring tape = 2.52 %

Note that it is dimension less becauseit is just the ratio of two same dimension scalars multiplied by hundred .