Ampère’s circuital law: loop, surface and enclosed currentऐम्पियर का परिपथीय नियम: लूप, पृष्ठ और परिबद्ध धाराAmpère’s circuital law: loop, surface and enclosed current

NCERT Fig 4.12 · Class 12 Physics · Chapter 4 · interactive diagram

Parts and what they mean

• Closed loop C (boundary of the surface) (बंद लूप C (पृष्ठ की परिसीमा)) — We add up B·dl all the way round it.
• Open surface bounded by C (C से परिबद्ध खुला पृष्ठ) — Count the current that passes through it.
• Line element dl (रेखा अवयव dl) — Along the loop, in the sense we go round.
• Current I₁ through the surface (पृष्ठ से गुज़रती धारा I₁) — Counted as positive: curl right-hand fingers along C → thumb gives + direction.
• Current I₂ through the surface (पृष्ठ से गुज़रती धारा I₂) — Also enclosed, so it counts.
• Current I₃ outside the loop (लूप के बाहर धारा I₃) — Not enclosed: it changes B at points, but adds nothing to ∮B·dl.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 4.12. Report a mistake