in page 10 of ncert chem. book it is given in point no.4 of significant figures that  100 has 1 significant figure while in point no.5 it is given 2 balls or 20 eggs have infinite significant figures but both 100 and 20 or 2 are counting nos. then why such difference?please clear my doubt.

Dear student
Please find the solution to the asked query:

If you read the textbook carefully, it is written that 100 has one significant figure, which is true, because if decimal point is not mentioned, the trailing zeros are not considered as significant. So there is only one significant number in 100.

In the point 5, however it is mentioned that 2 balls and 20 eggs have infinite significant figures as these numbers are counted with the objects, as 2 balls and not simply 2, or 20 eggs. Hence these are precisely referred as counting numbers of objects.These numbers are thus exact and thus can be represented by writing infinite number of zeros after placing a decimal. example: 2 can be written as 2.00000 and 20 = 20.000000

Hope this information will clear your doubts regarding the topic. If you have any other doubts please ask here on the forum and our experts will try to solve them as soon as possible.


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