Everything Science Grade 10

CHAPTER 16. ELECTROSTATICS 16.3

Step 1:Analyse the problem

In the first case, we have a sphere with positive charge which isat-

tractingthe left charged sphere. We need to find the charge on the left

sphere.

Step 2:Identify the principles

We are dealing with electrostatic forces between charged objects. There-

fore, we know thatlikechargesrepeleach other andoppositecharges

attracteach other.

Step 3:Apply the principles

a. In the first case, the positively charged sphere is attracting the left

sphere. Since an electrostatic force between unlike charges is attrac-

tive, the left sphere must benegativelycharged.

b. In the second case, the positively charged sphere repels the left

sphere. Like charges repel each other. Therefore, the left sphere

must now also bepositivelycharged.

Conservation of charge ESAEU

In all of the examples we’ve looked at charge was not created or destroyed but it moved

from one material to another.

DEFINITION: Principle of conservation of charge

The principle of conservation of charge states that the net charge of an iso-

lated system remains constant during any physical process, e.g. two charge

objects making contacting and separating.

Physics: Electricity and Magnetism 265