Question

The work done in bringing three particles each of mass $10gm$ from large distances to the vertices of an equilateral triangle of side $10cm$ is

• A. ${10}^{-13}J$
• B. $2\times {10}^{-13}J$
• C. $4\times {10}^{-11}J$
• D. ${10}^{-11}J$

Answer 1

The correct option is B $2\times {10}^{-13}J$

Work done is given by-

$W=-U=-(-\frac{3G{m}_1{m}_2}{r})=\frac{3G{m}_1{m}_2}{r}$

$W=\frac{3\times 6.67\times {10}^{-11}\times ({10}^{-2}{)}^2}{{10}^{-1}}=2\times {10}^{-13}J$