Before thunder, the hair stands on end. A hair with a mass of 0.50 ng and a charge of 1.0 pC is supported by a force other than the weight of the hair and the electric force. What is the electric field strength?
Correct answer: A. 4.9 x 10^3 N C-1
- A. 4.9 x 10^3 N C-1
- B. 4.9 x 10^6 N C-1
- C. 4.9 x 10^5 N C-1
- D. 4.9 x 10^9 NC-1
Explanation
The electric force is equal to the weight.Electric force = Weight Eq = mgElectric field strength E = mg / q {mass should be in kg.)E = [(0.50 μg) × (9.8 m/s²)] / (1.0 pC)Now, let's plug in the values and convert units if needed:1 μg = 10^-9 kg1 pC = 10^-12 CE = [(0.50 × 10^-9 kg) × (9.8 m/s²)] / (1.0 × 10^-12 C)E = [4.9 × 10^-9 kg m/s²] / (1.0 × 10^-12 C)E = 4.9 × 10³ N/CSo, the electric field strength is 4.9 × 10³ N/C.
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Electrostatics describes forces between charges through Coulomb's law, electric fields and field intensity, then uses electric potential to measure energy per unit charge. Capacitors store charge and electrical energy, with capacitance depending on geometry and dielectric material, not simply on the amount of charge present.
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