10 questions · Form 3 Mathematics Bab 2: Standard Form
How many significant figures are there in 0.005040?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. How many significant figures are there in 0.005040?
Answer: B
Leading zeros (0.00) are not significant. The digits 5, 0, 4, and the trailing zero 0 are significant, giving 4 s.f.
2. Find the value of (3.0 × 10⁴)² and state the answer in standard form.
Answer: A
(3.0)² × (10⁴)² = 9.0 × 10⁴ˣ² = 9.0 × 10⁸.
3. Calculate (2 × 10⁴) × (3 × 10⁻⁶).
Answer: A
(2 × 3) × 10⁴⁺⁽⁻⁶⁾ = 6 × 10⁻².
4. A rectangular land has length 4 × 10³ m and width 2.5 × 10² m. Find the area of the land in m² in standard form.
Answer: A
Area = length × width = (4 × 10³) × (2.5 × 10²) = (4 × 2.5) × 10³⁺² = 10 × 10⁵ = 1.0 × 10⁶ m².
5. Calculate (8 × 10⁻³) ÷ (4 × 10⁻⁷).
Answer: B
(8 ÷ 4) × 10⁻³⁻⁽⁻⁷⁾ = 2 × 10⁻³⁺⁷ = 2 × 10⁴.
6. Evaluate (1.2 × 10³) × (5 × 10⁴) and state the answer in standard form.
Answer: B
(1.2 × 5) × 10³⁺⁴ = 6.0 × 10⁷.
7. Round 49,960 to 3 significant figures.
Answer: A
Target position is the second 9. Next digit is 6 (≥ 5), rounding up gives 50,000 (which represents 3 s.f. in this context).
8. Calculate 6.2 × 10⁵ - 4.1 × 10⁴.
Answer: D
6.2 × 10⁵ - 0.41 × 10⁵ = (6.2 - 0.41) × 10⁵ = 5.79 × 10⁵.
9. How many significant figures does the number 300.00 have?
Answer: C
Trailing zeros after a decimal point are significant. All 5 digits (3, 0, 0, ., 0, 0) are significant.
10. If 0.0000072 = 7.2 × 10ⁿ, find the value of n.
Answer: A
Moving decimal 6 places to the right gives n = -6.