The field strength of a point charge at a distance R1 = 20 cm from it E1 = 100v / m

The field strength of a point charge at a distance R1 = 20 cm from it E1 = 100v / m Determine the field strength at a distance R = 40 cm from the charge.

Initial data: R1 (first distance to the point charge) = 20 cm (0.4 m); E1 (field strength at the first point) = 100 V / m; R2 (second distance to charge) = 40 cm (0.4 m).

The field strength at a distance of 40 cm from the charge is determined from the equality (E = k * | q | / r ^ 2): k * | q | = Е1 * r1 ^ 2 = Е2 * r2 ^ 2, whence Е2 = Е1 * r1 ^ 2 / r2 ^ 2.

Calculation: E2 = 100 * 0.2 ^ 2 / 0.4 ^ 2 = 25 V / m.

Answer: At a distance of 40 cm from the charge, the field strength is 25 V / m.