Two equally charged identical small balls kept some fixed distance apart exert a repulsive force F on each other. A similar uncharged ball, after touching one of them is placed at the mid-point of line joining the two balls. Force experienced by the third ball is

Question

Two equally charged identical small balls kept some fixed distance apart exert a repulsive force F on each other. A similar uncharged ball, after touching one of them is placed at the mid-point of line joining the two balls. Force experienced by the third ball is (A) 4 F (B) 2 F (C) F (D) (F/2)

Tardigrade Admin · Accepted Answer

F1=F=(K Q2/r2) ...(i)

|F textNet|=|F2-F1| =(K Q2 4/4 r2)-(K Q2 4/2 r2) (K Q2/r2)=F Force remain's constant

Q. Two equally charged identical small balls kept some fixed distance apart exert a repulsive force $F$ on each other. A similar uncharged ball, after touching one of them is placed at the mid-point of line joining the two balls. Force experienced by the third ball is

$4 F$

$2 F$

$F$

$\frac{F}{2}$

$F_{1} = F = \frac{K Q ^{2}}{r ^{2}} ... (i)$

$∣ F_{Net} ∣ = ∣ F_{2} - F_{1} ∣$
$= \frac{K Q ^{2} 4}{4 r ^{2}} - \frac{K Q ^{2} 4}{2 r ^{2}}$
$\frac{K Q ^{2}}{r ^{2}} = F$
Force remain's constant

Q. Two equally charged identical small balls kept some fixed distance apart exert a repulsive force F on each other. A similar uncharged ball, after touching one of them is placed at the mid-point of line joining the two balls. Force experienced by the third ball is

4F

2F

F

2F​

F1​=F=r2KQ2​...(i) ∣FNet​∣=∣F2​−F1​∣ =4r2KQ24​−2r2KQ24​ r2KQ2​=F Force remain's constant

Q. Two equally charged identical small balls kept some fixed distance apart exert a repulsive force $F$ on each other. A similar uncharged ball, after touching one of them is placed at the mid-point of line joining the two balls. Force experienced by the third ball is

$4 F$

$2 F$

$F$

$\frac{F}{2}$

$F_{1} = F = \frac{K Q ^{2}}{r ^{2}} ... (i)$

$∣ F_{Net} ∣ = ∣ F_{2} - F_{1} ∣$
$= \frac{K Q ^{2} 4}{4 r ^{2}} - \frac{K Q ^{2} 4}{2 r ^{2}}$
$\frac{K Q ^{2}}{r ^{2}} = F$
Force remain's constant