10 questions · Form 3 Mathematics Bab 2: Standard Form
10 questions · plays in fullscreen
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Calculate (2 × 10⁴) × (3 × 10⁻⁶).
Answer: A
(2 × 3) × 10⁴⁺⁽⁻⁶⁾ = 6 × 10⁻².
2. Calculate (8 × 10⁻³) ÷ (4 × 10⁻⁷).
Answer: B
(8 ÷ 4) × 10⁻³⁻⁽⁻⁷⁾ = 2 × 10⁻³⁺⁷ = 2 × 10⁴.
3. Calculate 3.4 × 10⁴ + 2.5 × 10⁴.
Answer: B
(3.4 + 2.5) × 10⁴ = 5.9 × 10⁴.
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. Express 0.0000407 in standard form.
Answer: A
Move the decimal point 5 places to the right: 0.0000407 = 4.07 × 10⁻⁵.
6. 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.
7. 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.
8. Express 583,000 in standard form.
Answer: C
Move the decimal point 5 places to the left: 583,000 = 5.83 × 10⁵.
9. The mass of a water molecule is 3 × 10⁻²³ g. Calculate the mass of 4 × 10²¹ water molecules.
Answer: B
Total mass = (3 × 10⁻²³) × (4 × 10²¹) = 12 × 10⁻² = 1.2 × 10⁻¹ g.
10. Simplify 0.00012 ÷ (3 × 10⁻²).
Answer: A
0.00012 = 1.2 × 10⁻⁴. (1.2 × 10⁻⁴) ÷ (3 × 10⁻²) = (1.2 ÷ 3) × 10⁻⁴⁻⁽⁻²⁾ = 0.4 × 10⁻² = 4 × 10⁻³.