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Explore the quantitative relation between equipotential lines and the electric field, visualizing field lines as topographic maps to understand their direction and magnitude. Learn about conductors, dielectric strength, capacitance, and parallel-plate capacitors.
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Equipotential lines and the Electric field: Quantitative relation
Equipotential lines and the Electric field: Quantitative relation ?
Equipotential lines and the Electric field: Quantitative relation
Small enough scale, looks like parallel plate field: (calculate)
Formally: Direction: downhill
Pretending that V(x) is like a topographic map: The Electric field always points in the direction of steepest descent! B) The magnitude of the electric field is given by the slope in that direction! alternate units for E: V/m
Note: color Scheme is backward
Example 17.22 where’s V = 0? 5 cm Two possibilities!
Example 17.22 where’s V = 0? Possibility #1 5 cm x
Example 17.22 where’s V = 0? Possibility #2 x
Electric fields just outside of a conductor are strong where the conductor is pointy: Dielectric strength of a material = maximum electric field the Material can stand before breaking down. Dielectric strength of air = 3 × 106 V/m Example: Voltage of a 8 cm spark!
Capacitance: Must be at different potentials!
10 cm Parallel-plate capacitor: 10 cm 0.1 cm Square plates
Parallel-plate capacitor: Dielectric constant! Quartz: k = 4.3 Dielectric! 10 cm 0.1 cm Square plates
V de G demo again, big and little spheres – spark size Leyden-jar demo