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MYP Physics · 08 · data analysis

Pressure below an unknown liquid

Pressure and fluids · Original GioPhysics question with a detailed, mark-by-mark answer guide.

Demand
routine
Marks
7
Topics
2
Answer
Complete
data analysis7 marks

A pressure sensor measures gauge pressure below the surface of a liquid. Gauge pressure excludes atmospheric pressure. Use g = 10 N kg⁻¹.

Gauge pressure at different depths
Depth / mGauge pressure / Pa
0.05400
0.10800
0.151200
0.201600
  1. a

    Describe Describe the pattern supported by the data.

    2 marks
  2. b

    Determine Use p = ρgh to determine the liquid's density.

    3 marks
  3. c

    Predict Predict the gauge pressure at a depth of 0.35 m and state one model assumption.

    2 marks
Ready to self-mark?Reveal the detailed answer guide
Answer overviewKey answer: States that gauge pressure is directly proportional to depth. Supports the statement, for example by noting that doubling depth doubles pressure. Rearranges to ρ = p ÷ (gh).
01

a

2 marks

Describe Describe the pattern supported by the data.

How to approach it

Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.

  1. 1

    States that gauge pressure is directly proportional to depth.

  2. 2

    Supports the statement, for example by noting that doubling depth doubles pressure.

02

b

3 marks

Determine Use p = ρgh to determine the liquid's density.

How to approach it

Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.

  1. 1

    Rearranges to ρ = p ÷ (gh).

  2. 2

    Substitutes a consistent pair, for example 1600 ÷ (10 × 0.20).

  3. 3

    Obtains density = 800 kg m⁻³.

03

c

2 marks

Predict Predict the gauge pressure at a depth of 0.35 m and state one model assumption.

How to approach it

Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.

  1. 1

    Calculates p = 800 × 10 × 0.35 = 2800 Pa.

  2. 2

    States a relevant assumption such as constant liquid density, uniform gravitational field, or a stationary connected liquid.

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