Question

1. how many significant figures are in the following numbers? (a) 78.9 ± 0.2 (b) 3.788 × 10⁹ (c) 2.46 × 10⁻⁶ (d) 0.005 3

Explanation:

Step1: Analyze (a) 78.9 ± 0.2

For measured values with uncertainty, we use the significant figures of the main measured number. All non-zero digits are significant.
78.9 has 3 non-zero digits.

Step2: Analyze (b) 3.788 × 10⁹

In scientific notation, all digits in the coefficient are significant.
3.788 has 4 non-zero digits.

Step3: Analyze (c) 2.46 × 10⁻⁶

In scientific notation, all digits in the coefficient are significant.
2.46 has 3 non-zero digits.

Step4: Analyze (d) 0.0053

Leading zeros are not significant; only non-zero digits and zeros between them count.
0.0053 has 2 non-zero digits.

Answer:

(a) 3
(b) 4
(c) 3
(d) 2