Question

Two identical charges repel each other with a force equal to 10 mg wt, when they are 0.6 m apart in air. The value of each charge is : (g = 10 ms^–2)

• A. 2 mC
• B. 2 × 10^–7 C
• C. 2 nC
• D. 2 mC

Answer 1

Answer: (D)

2 mC

Answer 2

F = 10 × 10^–3 × 10 N = 10^–1

F = q = $\sqrt { \frac { \mathrm { Fr } ^ { 2 } } { \mathrm {~K} } }$

= $\sqrt { \frac { .1 \times .36 } { 9 \times 10 ^ { 9 } } }$= 2 × 10^–6C