WHAT IS SIGNIFICANT FIGURES AND WHAT ARE THE USES ?

Dear rahul,

Every measurement has a degree of uncertainty associated with it. The uncertainty derives from the measuring device and from the skill of the person doing the measuring. Let's use volume measurement as an example. Say you are in a chemistry lab and need 7 mL of water. You could take an unmarked coffee cup and add water until you think you have about 7 milliliters. In this case, the majority of the measurement error is associated with the skill of the person doing the measuring. You could use a beaker, marked in 5 mL increments. With the beaker, you could easily obtain a volume between 5 and 10 mL, probably close to 7 mL, give or take 1 mL. If you used a pipette marked to with 0.1 mL, you could get a volume between 6.99 and 7.01 mL pretty reliably. It would be untrue to report that you measured 7.000 mL using any of these devices, because you didn't measure the volume to the nearest microliter. You would report your measurement using significant figures. These include all of the digits you know for certain plus the last digit, which contains some uncertainty.

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Sagar Singh

B.Tech IIT Delhi

To be very general u can say them approximation.They are used to figure out a single whole number nearest to it such that the error in counting is least.

significant figures are the number of meaningful digits in a number

for example

2.308 has four significant figures.

while doing any experiment,there is some uncertainity in the experiment.

this uncertainity is expressed by writing the number of significant figures of the value obtained.