Question

a charge +q exerts a force of magnitude-0.2n on another charge -2q.if they are separated by 25cm, determine the value of q

Answer 1

Answer:

Use coulomb s law

**Don't forget to convert cm to metres

$f = k \frac{q( - 2q)}{ {r}^{2} } \\ \implies - 0.2 = - 9 \times {10 }^{9} \times \frac{2 \times {q}^{2} }{ (\frac{1}{4}) {}^{2} } \\ \implies {q}^{2} = \frac{2}{2 \times 10 \times 16 \times 9 \times {10}^{9} } \\ \implies q = \frac{1}{4 \times 3 \times {10}^{5} } = 8.33 \times {10}^{ - 7} c$