A 4.0 µC point charge and a 3.0 µC point charge are a distance L apart. Where should a third point charge be placed so that the electric force on that third charge is zero? (Use the following as necessary: L.)

Respuesta :

Answer:

Q must be placed at 0.53 L

Explanation:

Given  data:

q_1 = 4.0 μC , q_2 = 3.0μC

Distance between charge is L

third charge q be placed at  distance x cm from q1

The force by charge q_1 due to q is

[tex]F1 = \frac{k q q_1}{x^2}[/tex]

[tex]F1 = \frac{k q ( 4.0 μC )}{ x^2}[/tex]                  ----1

The force by charge q_2 due to q is

[tex]F2 =  \frac{k q q_2}{(L-x)^2}[/tex]

[tex]F2 = \frac{kq (3.0 μC)}{(L-x)^2}[/tex]                   --2

we know that net electric force is equal to zero

F_1 = F_2

[tex]\frac{k q ( 4.0 μC )}{x^2}   =\frac{k q ( 3.0 μC )}{(l-x)^2}[/tex]

[tex]\frac{4}{3}*(L-x)^2 = x^2[/tex]

[tex]x = \sqrt{\frac{4}{3}*(L - x)[/tex]

[tex]L-x = \frac{x}{1.15}[/tex]

[tex]L = x + \frac{x}{1.15} = 1.86 x[/tex]

x = 0.53 L

Q must be placed at 0.53 L