Field Lines — Single Charge
Radial outward (+) or inward (−) lines with animated dots showing field direction.
Key Notes
E-field around a +charge points radially outward; around −charge, radially inward.
Number of lines per unit area is proportional to field magnitude — denser near the charge.
Field lines never cross — direction would be ambiguous.
Lines start on positive and end on negative charges (or extend to infinity).
Formulas
Point-charge field
Magnitude inverse-square in r.
Field line property
Shows local field direction.
Important Points
Density of lines is qualitative; |E⃗| is exact via Coulomb's law.
For a positive test charge, force is along the field line.
Number of lines from a charge ∝ q (Gauss's law foundation).
Field Lines — Single Charge notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 12 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.