Lesson eLearning

In a simple U‑tube manometer, the left arm contains a 2 m column of mercury higher than the right arm. What is the pressure difference between the two sides in pascals? (Use ρ = 13600 kg/m³ for mercury, g = 9.8 m/s²).

medium MCQ 2 marks Class 6 · Science · Air Around Us
  1. ≈ 2.7 × 10⁵ Pa
  2. ≈ 5.4 × 10⁴ Pa
  3. ≈ 1.8 × 10⁴ Pa
  4. ≈ 4.5 × 10⁵ Pa
Answer
≈ 2.7 × 10⁵ Pa

The correct answer is ≈ 2.7 × 10⁵ Pa — Round to significant figures: 2.7 × 10⁵ Pa.

Step-by-step solution

  1. Use the formula ΔP = ρgh.
  2. Insert ρ = 13600 kg/m³, g = 9.8 m/s², h = 2 m.
  3. Compute 13600 × 9.8 ≈ 133280.
  4. Multiply 133280 × 2 ≈ 266560 Pa.
  5. Round to significant figures: 2.7 × 10⁵ Pa.
Common mistake: Using wrong density of mercury or mis‑calculating height

Concept tested: Pressure difference using manometer

Published · How this solution was prepared and checked

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