Coulomb’s law & electric fields worksheet with answers

Two point charges of −4 µC and +10 µC are 12 cm apart. Find the magnitude of the electric force F between them. Use k = 8.99 × 10⁹ N·m²/C².

A proton (charge 1.602 × 10⁻¹⁹ C, mass 1.673 × 10⁻²⁷ kg) is in a uniform electric field of 2800 N/C. Ignoring gravity, find the magnitude of its acceleration a.

Charges of +2 µC and +8 µC are 100 cm apart. At what distance x from the +2 µC charge, on the line between them, is the electric field zero?

Charges of +1 µC and +3 µC are 30 cm apart. At what distance x from the +1 µC charge, on the line between them, is the electric field zero?

An electron enters the uniform field between two parallel plates moving parallel to them at 4 × 10⁷ m/s. The plates are 6 cm long and the field between them is 4400 N/C. Electron charge 1.602 × 10⁻¹⁹ C, mass 9.109 × 10⁻³¹ kg; ignore gravity. How far y is it deflected sideways when it leaves the plates? Give the answer in mm.

Three positive point charges sit at the corners of a right triangle: q₃ = 1 µC is at the right-angle corner, q₁ = 1 µC is 6 cm from it along one side and q₂ = 5 µC is 5 cm from it along the other side. Find the magnitude of the net electric force F on q₃.