Question

Write the number of significant digits in the following (a) 1001 (b)100.1 (c) 100.10 (d) 0.001001

Answer 1

Significant digits

The number of reliable known digits and the first uncertain digit gives the number of significant digits .

(a) 1001

Number of significant digits = 4

(b) 100.1

Number of significant digits = 4

(c) 100. 10

Number of significant digits = 5

(d) 0.001001

Number of significant digits = 4

Rules for significant digits

1. All non zero digits are significant
2. Zeroes after the decimal are not significant if they are succeeded by significant digits . 0.05 has 1 significant digits
3. Zeroes after the decimal digits are significant. 0.500 has 3 significant digits.
4. Zeroes between two significant figures are significant. 5.006 has 4 significant digits