Significant figures- tes.com

## Significant figures-

“The significant figures of a number are digits that carry meaningful contributions to its measurement resolution.”

## Rules  –

1. All non-zero numbers are significant.

Ex – 23.4 has 3 significant figures because all of the digits present are non-zero.

5.146 has 4 significant figures.

2. Zeros between two non-zero digits are significant.

3062  has 4 significant figures. The zero is between 3 and 6

3. Leading zeros are not significant. They represent the position of the decimal.

Ex –  0.054 has only 2 significant figures. All of the zeros are leading.

0.0063  has 2 significant figures.

4. Trailing zeros to the right of the decimal are significant.

67.00 has 4 significant figures.

67.000 has 5 significant figures.

5. Trailing zeros in a whole number with no decimal shown are not significant.

Ex – 650 has 2  significant figures.

1000 has 1 significant figure.

6. Exact numbers have an infinite number of significant figures.

1 meter = 1.00 meters = 1.0000 meters = 1.0000000000000000000 meters, etc.

7. For a number in scientific notation: N x 10n, all digits present in N are significant according to the above rules, the exponential term does not add to the significant figures.

Ex –  2.984  x 103 has 4 significant figures but the exponential term is not significant.

Rule 7 provides an opportunity to change the number of significant figures in the given value by changing its form.

Ex-  1100  has 2 significant figures according to rule 5, its two trailing zeros are not significant.  But if we write it in scientific notation that is  1.10 x 103, then it has 3 significant-figures.

Q – How many significant figures are in the following?

a) 3.356 gm

Significant figures= 4

b) 2.3 x 105

Significant figures= 2

c) 0.000169

Significant figures= 3

d) 37.000 gm

Significant figures= 5

e) 6.023 x 1023

Significant figures= 4

f) 1.6 x 10-19

Significant figures= 2