Finding Significant Figures in a Measurement

What is significant Figure?

The total number of digits (i.e. doubtful digit and confirm digits) in any measurement is known as significant figure.

Or

The digits that reflect the precision of the measurement are called significant figures.

Counting of Significant Figures in any Measurement:

Knowing the significant figures in a measure is based on the following rules-

(1) All non-zero numbers are significant figures.

For example, $46.3598$ has $6$ significant figures.

(2) All zero numbers between two non-zero numbers are significant figures.

For example, $600.8049$ has $7$ significant figures.

(3) If there is no non-zero number before the decimal point, then all the digits in the number except the zero numbers immediately after the decimal point are significant figures.

For example, $0.002809$ has $4$ significant figures.

(4) The zero after any non-zero digit to the right of the decimal point is a significant figure.

For example, $0.46920$ has $0$ significant figures.

(5) If a number is multiplied by a power of $10$, it does not affect the number of significant figures.

For example, $6.75\times 10^{3}$ has $3$ significant figures.

(6) Choosing different units does not change the number of significant figures.

For example, if a measurement is $2346 km$, then in different units, this measurement will be $23460 m$, $2346000 cm$ or $23460000 mm$. Here, the number of significant figures in each measurement is $4$.