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There are three attributes of every measured quantity - the amount, the unit of measurement, and the degree of precision to which the measurement was made. The latter, often ignored attribute, expresses itself by the number of significant figures in the numerical value. For instance 65000 has two significant digits and shows a lower degree of precision than 64982 with its five significant digits.

There are three questions in this Question Group. The questions are similar in terms of difficulty. Here is one of those questions:

Version 1:

Anna Litical is measuring the length of a magnesium strip using a centimeter ruler. She carefully places one end of the magnesium strip at the 0.00-cm mark and aligns the rest of the strip parallel to the ruler. The opposite end of the strip is shown. What is the proper means of reporting the measurement of the length of the magnesium strip?

 
14 cm
14.5 cm
14.7 cm
14.70 cm
15.0 cm
15 cm
 
 

Making a measurement - a proper one - may be more difficult than you think. Don't worry - we can help. The two graphics below should provide considerable help. The trick to a good measurement is providing an estimated digit. You can read about this below and see the three caterpillar examples that are given. But don't get squeamish because significant digits do not need to frighten you. Take your time. Use the markings on the device to determine the range the measured value falls into, and then provide an estimated digit that indicates where within the range the measurement is. You got this!

 


 
 


 

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