Resistance at Electron Scale

Also called

resistance · resistivity · electron drift · free electrons · Ohm's law · factors affecting resistance · length of a conductor · area of cross-section · copper wire · nichrome wire · heating effect of current · ammeter · voltmeter · metal ions · electric current · प्रतिरोध · विद्युत धारा · ओम का नियम · प्रतिरोधकता

Topics

• Resistance is the opposition a conductor offers to the flow of current; its SI unit is the ohm (Ω).
• Free electrons drift against the conventional current and keep colliding with the vibrating metal ions.
• Resistance is directly proportional to the length of a wire: doubling the length doubles the resistance.
• Resistance is inversely proportional to the area of cross-section: a thicker wire lets more current through.
• Resistance depends on the material: nichrome has a far higher resistivity than copper.
• Heating a metal makes its ions vibrate more, so electrons collide more often and the resistance rises.
• Ohm's law: V = IR. At a fixed temperature the current is proportional to the potential difference.
• R = ρl/A, where ρ (rho) is the resistivity of the material, l the length and A the area of cross-section.

About this model

A GLB file of about 416 KB, shown in Lably's 3D viewer and, on a phone, placed in your room with AR. Credit: Model, science and animation: Lably (built procedurally with three.js; no downloaded meshes). | CC BY 4.0. Original geometry and animation made for Lably.

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