Question

A test charge of +3 �C is at a point P where an external electric field is directed to the right and has a magnitude of 4 106 N/C. If the test charge is replaced with another test charge of -3 �C, the external electric field at P does which of the following? a). changes in a way that cannot be determined b). is undefined c). reverses direction

Answer 1

Answer:

C

Explanation:

The Coulomb's Law gives us the Electric Field strength of charge as follows:

E = k* (Q) / R^2

Where,

k : Coulomb constant 8.99 * 10^9 N /C

Q: Charge generating Electric Field strength

R: Distance from source to any point

In our case the value of E = 4.106 N /C is experienced by charge +3 C. This charge is replaced by an equal magnitude of charge but with negative sign -3 C. Scrutinizing on the above formula we can see that all quantities remain same hence, the magnitude of field strength remains same.

However, we also know a positive magnitude is directed away from the source charge while a negative magnitude is directed towards the source. We can conclude that only the direction of electric field reverses while magnitude remains same.