Mass of charge $Q$ is $m$ and mass of charge $2Q$ is $4\,m$ . If both are released from rest, then what will be $K.E.$ of $Q$ at infinite separation
A$\frac{{8K{Q^2}}}{{5r}}$
B$\frac{{4K{Q^2}}}{{5r}}$
C$\frac{{K{Q^2}}}{{4r}}$
D$\frac{{K{Q^2}}}{{2r}}$
Medium
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A$\frac{{8K{Q^2}}}{{5r}}$
a $\frac{\left(\mathrm{K}_{\mathrm{f}}\right)_{\mathrm{Q}}}{\left(\mathrm{K}_{\mathrm{f}}\right)_{2 \mathrm{Q}}}=\frac{4 \mathrm{m}}{\mathrm{m}}=\frac{4}{1}$
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