Two similar spheres having +q and -q charge a | vedclass

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Question

(C) Initially, the force between the two spheres with charges $+q$ and $-q$ separated by distance $r$ is given by Coulomb's Law: $F = k\frac{q^2}{r^2}

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$8F$ towards $-q$ charge

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(C) Initially, the force between the two spheres with charges $+q$ and $-q$ separated by distance $r$ is given by Coulomb's Law: $F = k\frac{q^2}{r^2}$.When a third sphere with charge $+q$ is placed at the midpoint (distance $r/2$ from both), it experiences two forces:$1$. Force due to the $+q$ charge at $A$: $F_A = k\frac{q \cdot q}{(r/2)^2} = 4k\frac{q^2}{r^2} = 4F$ (directed away from $A$, towards $C$).$2$. Force due to the $-q$ charge at $C$: $F_C = k\frac{q \cdot q}{(r/2)^2} = 4k\frac{q^2}{r^2} = 4F$ (directed towards $C$).The net force on the middle sphere is $F_{net} = F_A + F_C = 4F + 4F = 8F$.Since both forces are directed towards the $-q$ charge, the net force is $8F$ towards the $-q$ charge.

Two similar spheres having $+q$ and $-q$ charge are kept at a certain distance $r$. $A$ force $F$ acts between them. If another similar sphere having $+q$ charge is kept in the middle of the two spheres, then it experiences a force in magnitude and direction as:

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