Question

Three point charges are arranged on a line. Charge q3=+5.00x10^-9C and is at the origin. Charge q2=-3.00x10^-9C and is at x=+4.00cm. Charge q1 is at x=+2.00cm. What is the magnitude and sign (+ or -) for q1 if the net force on q3 is zero?
A. 0.750 nC
B. 0.520 nC
C. 0.975 nC
D. 0.000 nC

Answer 1

Answer:

The answer is 0.750 NC

Explanation:

I'm on the same test as well

Answer 2

Answer:

A. 0.750 nC

Explanation:

It is given that net electric force at q3 is 0,

So electric field because of q1 at origin=  electric field because of q2 at origin

$k\frac{q_{1} }{r_{1} ^{2} } =k\frac{q_{2} }{r_{2} ^{2} }$

$\frac{q_{1} }{r_{1} ^{2} } =\frac{q_{2} }{r_{2} ^{2} }$

${q_{1} } } =\frac{q_{2} }{r_{2} ^{2} }*{r_{1} ^{2}$

   =( -3.00x10^-9 x 2^2)/ 4^2

   =-0.750nC

It will have negative charge