Question

Two particles each with a charge of 1μC are separated a distance of 0.4 m. A test charge is placed just above them but directly between them. (b) What is the direction of the resultant electric field on the test charge?

Answer 1

Forces on the test (test is positive) charge

Σ Fx = 0 net result of x-compoment charges is zero

Σ Fy = 2 F sin θ where F is the force due to the distance of the test charge from one of the charges and sin θ is the component of that force that is perpendicular to the line separating the charges

The direction of the force is perpendicular to the line separating the two given charges