Electric flux through a small areaछोटे क्षेत्रफल से विद्युत फ्लक्सElectric flux through a small area

NCERT Fig 1.15–1.16 · Class 12 Physics · Chapter 1 · interactive diagram

Parts and what they mean

• Uniform electric field E (एकसमान विद्युत क्षेत्र E) — Parallel, equally spaced field lines = same E everywhere.
• Area facing the field (θ = 0) (क्षेत्र के सामने क्षेत्रफल (θ = 0)) — Normal along E, so the most field lines cross it: Δφ = EΔS (maximum).
• Tilted area element ΔS (झुका हुआ क्षेत्रफल अवयव ΔS) — Fewer lines cross it; only the projected area ΔS cos θ counts.
• Unit normal n̂ (area vector ΔS = ΔS n̂) (एकांक अभिलंब n̂ (क्षेत्रफल सदिश ΔS = ΔS n̂)) — The direction of an area is the direction of its normal; for a closed surface we take the outward normal.
• Normal parallel to E (E के समांतर अभिलंब) — cos 0 = 1, so flux is maximum.
• Angle θ between E and n̂ (E और n̂ के बीच कोण θ) — Δφ = EΔS cos θ. At θ = 90° the area is parallel to the field and the flux is zero.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 1.15–1.16. Report a mistake