There are two points charges, q1 = +5 nC, and q2 (unknown), fixed in place on th

Question

There are two points charges, q1 = +5 nC, and q2 (unknown), fixed in place on the x axis. At the location marked P, the net electric field due to both charges is zero: EP = 0 N/C. Based on the information what can you conclude about the magnitude and sign of the charge q2? Explain your reasoning without calculations.
****In the picture you can see that P is obviously closer to q2 than q1***
Specifically I need to know
What is the direction of the field E1 at P and why
What is the direction of the field at E2 at P and why.
What would the charge of q2 have to be and why
To determine the magnitude of q2 you need to know the magnitudes of E1 and E2 at p. So how would you find the magnitude of q2?
*** it is not important that I find a numerical answer. I need to more so understand the process and what is going on. It specifically says explain your reasoning without calculations. ****

Explanation / Answer

Since the electric field at p is 0, then E2=-E1. Their magnitude is equal, but direction is opposite. E1=kq1/r1^2 E2=kq2/r2^2 |E1|=|E2| kq1/r1^2=kq2/r2^2 q2/q1=r2^2/r1^2 since p is closer to q2, then r2 is smaller the r1, and r2^2/r1^2 is smaller then 1, so q2 is smaller then q1. The sign of q1 must be positive, since we need E2 to be in the opposite direction of E1. q1 is positive so E1 is from q1 to p, so E2 must be from q2 to p (I'm assuming that p is between q1 and q2, if it's not, then q2 must be negative). To calculate q2, we need to know q1, r1 and r2. once we know it we'll use: q2=q1r2^2/r1^2

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