1. The problem asks for the number of significant digits in the number $8.310 \times 10^3$. 2. Significant digits (or significant figures) are the digits in a number that carry meaningful information about its precision. 3. Rules for counting significant digits: - All non-zero digits are significant. - Zeros between non-zero digits are significant. - Leading zeros are not significant. - Trailing zeros in a decimal number are significant. 4. In $8.310 \times 10^3$, the digits are 8, 3, 1, and 0. 5. The zero after 1 is a trailing zero in the decimal part, so it is significant. 6. Therefore, the number $8.310 \times 10^3$ has 4 significant digits. Final answer: ii. 4