Using a cylinder simplifies the maths because its curved surface is always perpendicular to the electric field lines radiating from that straight wire, like spokes from a bicycle wheel. The flat ends don’t contribute, so the calculation becomes clean—just surface area times field strength. But I’ll tell you, the “infinite” part always makes me smile. My life is all finite lengths—the measured rope for tying up the bitter gourd vine, the exact plot for planting yarn. We choose the cylinder not because the world is infinite, but because we need a manageable shape to understand our small, orderly piece of it.
#exams#study
Jump in to reply — no account needed.