What are Significant figures and How to find Significant figures?

Significant figures are the important topic in physics and chemistry. If you don't know what are Significant figures and how to find significant figures then this article for you.
Here I am going to tell you all about Significant figures with their rules and examples.

Before leaning how to find Significant figures it is important to know what actually Significant figures are?

What are Significant figures?

Significant figures are related to number and digits in which zero is primary factor to decide the number of Significant figures in a given number.

All the figures expressed in reporting a reading of measurement are Significant figures.
However, the last non-zero figure is uncertain.

Example:  In a given number 1.0045 has five Significant figures.
In this example all digit has been counted.

Rules to find Significant figures :

* In a given number, All non-zero digits are significant.(irrespective the position of decimal point)

Examples:
⇒   1.325 g  has four significant figures.
⇒   2132 kg  has also four significant figures.

* If the given number is less than one and zero is placed between the decimal point and the non-zero digit, then in that case those zeros will not be significant.

Examples:
⇒   0.0532 g has three significant figures.
⇒   0.00004 g has one significant figures.

* If zero is placed between two non-zero digits, then in that case those zero will be significant.(irrespective the position of decimal point)

Examples:
⇒   1002 kg  has four significant figures.
⇒   3.002 g  has four significant figures.

* If the given number has no decimal point, in that case if all zero present after last of the non-zero digits then those zeros will not be significant.
But in actual measurement of a physical quantity they become significant.

Examples:
⇒    1250 kg has three significant figures.
⇒    125 km = 125000 m = 12500000 cm  has only three significant figures.

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