Question

12) Two point charges q₁ and q₂ are at distance 3 m. The sum of these charges is 20 $\mu C$. If a charge repels the other with a force of 0.075 N. Then calculate the value of both the charges.
$(Answer:15\mu Cand5\mu C)$

Answer 1

Dear Student,
$$\begin{gathered} Accordingtoquestion \\ K\frac{q_1{q}_2}{3^2}=.075 \\ {q}_1{q}_2=\frac{.075\times 9}{9\times {10}^9}=75\times {10}^{-12} \\ but \\ {q}_1+q_2=20\times {10}^{-6}C---1 \\ {q}_1-q_2=\sqrt{{\left(q_1+q_2\right)}^2-4q_1{q}_2}=\sqrt{400\times {10}^{-12}-300\times {10}^{-12}}={10}^{-6} \\ {q}_1-q_2=10\times {10}^{-6}C---2 \\ aftersolvong1and2weget \\ {q}_1=15\mu C \\ and \\ {q}_2=5\mu C \end{gathered}$$
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