A point charge produces a radial field: lines stream straight out (positive) or straight in (negative), and the field strength is E = Q / (4πε₀r²). Because of the r² in the denominator, the field weakens rapidly with distance. Move the test point and read the field off the inverse-square curve.
MissionPredict how the field strength of a point charge varies with distance.Streak 0Best 0
The electric field strength of a point charge varies with distance as:
field strength E = Q / (4πε₀r²)—
directionoutward
The marker on the curve sits at your chosen distance. Halving r makes the field four times as strong; the lines never cross.