Two point charges ${q}_{1}=3\mu C$ and ${q}_{2}=-4\mu C$ are placed at points $(2\overset{^}{i}+3\overset{^}{j}+3\overset{^}{k})$ and $(\overset{^}{i}+\overset{^}{j}+\overset{^}{k})$ respectively. Force on charge ${q}_{2}$ is _________ N. (Take $\frac{1}{4\pi {ϵ}_{0}}=9\times {10}^{9}$ SI Units) [JEE Main 2026, 8 Apr (Shift 2)]

Question

YESPYQ · Accepted Answer

Correct answer: b) $(4\overset{^}{i}+8\overset{^}{j}+8\overset{^}{k})\times {10}^{-3}$. Vector from ${q}_{1}$ to ${q}_{2}$ : $\vec{r}={\vec{r}}_{2}-{\vec{r}}_{1}=-\overset{^}{i}-2\overset{^}{j}-2\overset{^}{k}$ Distance: $r=\sqrt{1+4+4}=3$ Force on ${q}_{2}$ : $\vec{F}=\frac{1}{4\pi {\epsilon }_{0}}\frac{{q}_{1}{q}_{2}}{{r}^{3}}\vec{r}$ Since ${q}_{1}=3\mu C$ and ${q}_{2}=-4\mu C$, the force is attractive, hence along $\overset{^}{i}+2\overset{^}{j}+2\overset{^}{k}$ $\Rightarrow \frac{9\times {10}^{9}\times (3)(4)\times {10}^{-12}}{27}(\overset{^}{i}+2\overset{^}{j}+2\overset{^}{k})$ $\Rightarrow 4\times {10}^{-3}[\overset{^}{i}+2\overset{^}{j}+2\overset{^}{k}]$

Two point charges \({q}_{1}=3\mu C\) and \({q}_{2}=-4\mu C\) are placed at points \((2\overset{^}{i}+3\overset{^}{j}+3\o…

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