Question

two point charges A and B are R distance apart. a third point charge placed on the perpendicular bisector at a distance d from the centre will experience maximum electrostatic force when...

Answer 1

QUESTION:

Two point charges A and B are R distance apart. a third point charge placed on the perpendicular bisector at a distance d from the centre will experience maximum electrostatic force when...

SOLUTION:

Let's assume that all charges are similar. Hence, total force, acting on the third charge, according to the law of cosines is

$$F _ {t o t a l} = \sqrt {F _ {1} ^ {2} + F _ {2} ^ {2} - 2 F _ {1} F _ {2} \cos \alpha}$$

So, maximum total force is reached when

$$\cos \alpha = 0$$

or

$$\alpha = 9 0 {}^ {\circ}$$

Or when triangle ABC is a right triangle, and angle $\mathrm{ACB} = 90{}^{\circ}$

ANSWER

So, maximum total force is reached when

$$\cos \alpha = 0$$

or

$$\alpha = 9 0 {}^ {\circ}$$

Or when triangle ABC is a right triangle, and angle $\mathrm{ACB} = 90{}^{\circ}$