b
(b) \(F_A\) = force on \(C\) due to charge placed at \(A\)
\( = 9 \times {10^9} \times \frac{{{{10}^{ - 6}} \times 2 \times {{10}^{ - 6}}}}{{{{(10 \times {{10}^{ - 2}})}^2}}} = 1.8\,N\)
\(F_B\) = force on \(C\) due to charge placed at \(B\)
\( = 9 \times {10^9} \times \frac{{{{10}^{ - 6}} \times 2 \times {{10}^{ - 6}}}}{{{{(0.1)}^2}}} = 1.8\,N\)
Net force on \(C\)
\({F_{net}} = \sqrt {{{({F_A})}^2} + {{({F_B})}^2} + 2{F_A}{F_B}\cos {{120}^o}} = 1.8\,N\)
