Question

find thepoint on line joining the two charges +12nc &+3nc where resultant field is zero distance between the charges 1.2m​

Answer 1

Answer:

Check the pic for answer

Answer 2

Given:

Two charges

q₁ = 12 nC and q₂ = nC

Distance (d) = 1.2 m

To find:

A point on the line joining the charges where the resultant field is 0.

Solution:

Let a charge q₃ be at a point P lying on the line joining q₁ and q₂ where the resultant field is will be 0 be at a distance of x m from the charge q₁ therefore, it distance from q₂ will be (1.2 -x) m.

Hence, given that

$E_{q_{1}q_{3} } + E_{q_{3} q_{2} } = 0$

Therefore,

$E_{q_{1} q_{3} } = -(E_{q_{2} q_{3} })$

Hence,

$K\frac{q_{1} }{x^{2} } = -(K \frac{ q_{2} }{(1.2 -x)^{2} } )$  

$\frac{q_{1} }{x^{2} } = -\frac{q_{2} }{(1.2 -x)^{2} }$

or

$\frac{12}{x^{2} } = \frac{3}{(1.2-x)^{2} }$

$(\frac{x}{1.2-x} )^{2} = 4$

$x= 2(1.2-x)\\x=2.4-2x\\3x=2.4$

or

$x = 0.8 m$

Final answer:

Hence, the point at which the resultant field because of two charges will be 0 is 0.8 m .