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General Physics II · Figure Sources and Reproduction

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All eleven WebP files in this directory are original explanatory diagrams or computed plots, created for these notes. No textbook artwork, lecture-slide bitmap, classroom screenshot, or third-party image is embedded. The diagrams express the physics developed in the supplied lessons; numerical plots are generated directly from the equations.

The original figures and their authoring script are made available under CC BY 4.0; attribute them to Tsukimakura's notebook — General Physics II figures. This permission applies to these new figures and the authoring script, not to the local course PDFs, screenshots, or demonstration archive. See the CC BY 4.0 license.

Figure inventory

File Content / mathematical basis
charge-field-lines.webp Numerical superposition of two equal positive charges and of a dipole.
dipole-torque-energy.webp Dipole forces in a uniform field and \(U=-pE\cos\theta\).
ring-disk-axis.webp Ring symmetry/projection and dimensionless ring/disk field shapes.
gaussian-surfaces.webp Spherical, planar, and cylindrical Gaussian surfaces and flux factors.
sphere-field-potential.webp Exact radial field/potential curves for a uniform insulating ball and an isolated spherical conductor.
electrostatics-triangle.webp Relations between \(\rho_q\), \(\mathbf E\), and \(V\).
grounded-plane-image.webp Auxiliary image construction, physical upper-region field lines, and equipotential contours.
sphere-uniform-field.webp Exterior field of a neutral conducting sphere in a uniform field and its cosine surface density.
spherical-image-geometry.webp Physical/image locations for exterior-sphere and cavity problems.
current-drift.webp Qualitative random-plus-drift motion and current-section geometry.
capacitor-geometries.webp Parallel-plate and coaxial-cylinder geometries.

Reproduction

The editable originals are the equation-based plotting instructions in scripts/generate_gp2_figures.py, relative to the repository root. The site itself only needs the committed WebP files; plotting libraries are optional authoring dependencies and are not added to the normal MkDocs environment.

With Python, NumPy, Matplotlib, and Pillow available, run from the repository root:

MPLCONFIGDIR=/tmp/gp2-matplotlib python3 scripts/generate_gp2_figures.py

The script uses a fixed random seed for the drift sketch and exports images at 160 dpi before WebP conversion. All figure labels are English so the mathematical labels remain portable across systems without Chinese fonts.

Interpretation limits

  • Numerical streamlines are visualization samples. Their algorithmic density does not represent an exact number of field lines per area and should not be used to infer a field-strength ratio.
  • Charge singularities are masked in field plots.
  • Field-line figures show planar slices of three-dimensional point-charge fields.
  • The lower half of the plane-image figure is an auxiliary construction, not the physical field inside the conductor.
  • The conductor's interior is excluded from the uniform-field sphere's exterior streamlines.
  • The ring and disk curves have explicitly different normalizations; compare their shapes rather than their absolute values.
  • The random-plus-drift figure is schematic, not a simulated scattering trajectory or a fitted material measurement.