Question 232: Units , Dimensions and Error Analysis

Question

A student in the laboratory measures thickness of a wire using screw gauge. The readings are 1.22 mm, 1.23 mm, 1.19 mm and 1.20 mm. The percentage error is $${x \over {121}}\% $$. The value of x is ____________.

Accepted Answer

$${I_{mean}} = {{1.22 + 1.23 + 1.19 + 1.20} \over 4} = 1.21$$
$$\Delta {I_{mean}} = {{0.01 + 0.02 + 0.02 + 0.01} \over 4} = 0.015$$
So % $$I = {{\Delta {I_{mean}}} \over {{I_{mean}}}} 	imes 100 = {{0.015} \over {1.21}} 	imes 100 = {{150} \over {121}}\% $$
$$x = 150$$

Units , Dimensions and Error Analysis

A student in the laboratory measures thickness of a wire using screw gauge. The readings are 1.22 mm, 1.23 mm, 1.19 mm and 1.20 mm. The percentage error is ${x \over {121}}\% $. The value of x is ____________.

Choose the correct answer: