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Q.
The most accurate reading of the length of a $6.28\, cm$ long fibre is
Physical World, Units and Measurements
Solution:
Most accurate reading is the one having minimum error.
So, $16-6.281=0.28\, cm$
$16.5-6.281=0.22\, cm$
$15.99-6.281=0.29\, cm$
$16.0-6.281=0.28\, cm$
So, second reading is most accurate.