The number of significant figures in the sum of 1.21 x 10^5 and 3.26 x 10^3 is
Correct answer: D. 8
- A. 3
- B. 5
- C. 6
- D. 8
Explanation
To find the number of significant figures in the sum of 1.21 × 105 and 3.26 × 103, first, convert both numbers to the same power of ten: 1.21 × 105 = 121000 and 3.26 × 103 = 3260. Add them to get 124260. When written in scientific notation, this becomes 1.24260 × 105, which has 8 significant figures. Thus, Option D is correct, while the other options underestimate the number of significant figures due to incorrect alignment or rounding.
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About Errors and Significant Figures
Measurement errors include random and systematic effects, absolute, fractional and percentage uncertainty, and the precision shown by significant figures. Questions apply rounding rules and uncertainty propagation in addition, subtraction, multiplication and division, while distinguishing accuracy from precision and uncertainty from an actual mistake.
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