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Mission SE10 Electric Field

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 The Question

A charge Q creates an electric field. A test charge q is used to measure the strength of the electric field at a distance d from Q. The electric field strength is defined as ____.

 Define Help

Definition of Electric Field Strength:
Any source of charge Q will create an electric field in the space surrounding it. The strength of an electric field (E) at any given location in this space can be determined by placing a test charge q in the space and measuring the force (F) that is exerted upon it. The electric field strength is defined as the amount of force per unit of charge on the test charge.

E = F / q

 Bright Idea

It is easy to become confused by the mathematics of electric field strength. It is important to bear in mind that there are always two charges involved in any electrical interaction. In this case, the charges are Q and q. Big Q represents the source charge which creates the electric field. Little q represents the test charge which is used to measure the strength of the electric field at a given location surrounding the source charge. Give considerable attention to the charge quantity - Q or q - being used in each equation.

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