IB Physics HL S2.3 Concluding and Evaluating Question Bank

Practise IB Physics HL S2.3 by testing conclusions against uncertainty, model limits and competing explanations in extended investigations.

Exam points

design and evaluate investigations using valid measurements, controls, uncertainty and evidence
process data with graphs, trends, relationships and justified conclusions
communicate a reproducible method and assess limitations with realistic improvements

Covered syllabus points

S2.3.1—Concluding S2.3.2—Evaluating

[Maximum number: 1]

A group of students is trying to determine the density and the viscosity of a liquid.

To determine the density, they use a balance to read the mass m of a sphere in air and immersed in the liquid.

They use a sphere of volume $V=1.827 \times 10^{-7} \mathrm{~m}^{3}$ .
The readings are $m_{\text {air }}=1.427 \mathrm{~g}$ in air and $m_{\text {immersed }}=1.208 \mathrm{~g}$ in the liquid.
The readings are different due to buoyancy. The buoyancy force $F_{\mathrm{b}}$ is given by

F_{\mathrm{b}}=\rho V g

where V is the volume of the sphere and $\rho$ is the density of the liquid.

The students search literature values and find the viscosity of this liquid to be 0.24 , when expressed in SI base units.

Suggest a conclusion reached by the students.

[Maximum number: 1]

A boat is moved from land to water by rolling it across a set of cylindrical airbags.

Figure for Question S2.3 Concluding and evaluating question 2 — IB Physics HL

When fully inflated, an unloaded airbag has a diameter of 1.80 m and a length of 24.0 m . At a temperature of $15^{\circ} \mathrm{C}$ , an airbag can hold 4200 mol of gas.

Identify an assumption used in this estimation.

The boat is then released to roll down across the airbags. When the boat loses contact with an airbag at the top of the slope, the airbag expands adiabatically.

All question bank results loaded

Covered syllabus points

S2.3 Concluding and evaluating question 1

S2.3 Concluding and evaluating question 2