Significant figures-

## 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 10 ^{n}, 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 10^{3} 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 10^{3}, 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 10^{5}

Significant figures= 2

c) 0.000169

Significant figures= 3

d) 37.000 gm

Significant figures= 5

e) 6.023 x 10^{23}

Significant figures= 4

f) 1.6 x 10^{-19}

Significant figures= 2