Just before a thunderstorm, the hairs on your head may occasionally stand up. A hair with mass $0.50\,\text{mg}$ and charge $1.0\,\text{pC}$ is held in equilibrium by a force produced by an electric field. Ignore all forces apart from the weight of the hair and the electric force. Find the electric field strength?
- A$4.9 \times 10^3\,\text{N C}^{-1}$
- B$4.9 \times 10^5\,\text{N C}^{-1}$
- C$4.9 \times 10^6\,\text{N C}^{-1}$
- D$4.9 \times 10^9\,\text{N C}^{-1}$