# Homework Help: Problem Electric Fields

1. Apr 8, 2007

### simplicity12

1. The problem statement, all variables and given/known data
A negative charge of 2.4 X 10^-6 C experiences an electric force of magnitude 3.2 N, acting to the left.

a. Calculate the magnitude and direction of the electric field at that point.
b. Calculate the value of the field at that point if a charge of 4.8 X 10^-6 C replaces the charge of 2.4 X 10^-6 C.

2. Relevant equations
Electric field formula:
E= F(e)/q

3. The attempt at a solution
I answered part A correctly which is 1.3 X 10^6 N/C
. But I'm having problems with part b. Don't I just replace the q value of 2.4 X 10^-6 C with the new value 4.8 X 10^-6 C and solve for the electric field again? But the answer is 1.3 X 10^6 N/C
. Can someone help me with this?​

2. Apr 8, 2007

### robb_

The field is produced by the source charges. You can assume here that the test charge, that is the one you place in the field, does not affect the value of the field.

3. Apr 8, 2007

thank you :)