Field on the axis of a circular current loopवृत्ताकार धारा पाश की अक्ष पर क्षेत्रField on the axis of a circular current loop

NCERT Fig 4.9 · Class 12 Physics · Chapter 4 · interactive diagram

Parts and what they mean

• Circular loop, radius R (वृत्ताकार पाश, त्रिज्या R) — Lies in a plane perpendicular to the x-axis (seen at a slant).
• Current I (धारा I) — Steady current round the loop.
• Element dl at the top (⊙, towards you) (ऊपर अवयव dl (⊙, आपकी ओर)) — Every dl is perpendicular to its r, so |dl × r| = r dl.
• Opposite element at the bottom (⊗) (नीचे विपरीत अवयव (⊗)) — Its dB⊥ cancels that of the top element.
• r: from dl to P, r² = x² + R² (r: dl से P तक, r² = x² + R²) — Same length for every element of the loop.
• Radius R (त्रिज्या R) — Radius of the loop.
• Distance x of P from the centre (केंद्र से P की दूरी x) — Measured along the axis.
• Axial point P (अक्षीय बिंदु P) — B = μ₀IR² / 2(x² + R²)^(3/2), along +x here.
• dB from the top element (ऊपर वाले अवयव से dB) — Perpendicular to r (and to dl).
• dBx: component along the axis (dBx: अक्ष के अनुदिश घटक) — dBx = dB cos θ = dB·R/r. All of these add up.
• dB⊥: component across the axis (dB⊥: अक्ष के लंबवत घटक) — Cancelled by the opposite element.
• dB from the bottom element (नीचे वाले अवयव से dB) — Mirror image: same dBx, opposite dB⊥.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 4.9. Report a mistake