D.2 Electric and magnetic fields

• Direction of forces between the two types of electric charge.

• Coulomb’s law: F=kq1q2/r^2 for point charges; k=1/(4πε0).

• Conservation of electric charge.

• Millikan’s experiment as evidence for quantization of electric charge.

• Charge transfers by friction, electrostatic induction or contact.

• Grounding can remove or add charge.

• Electric field strength: E=F/q.

• Electric field lines.

• Relationship between field line density and field strength.

• Greater field-line density indicates stronger field.

• Uniform field between plates: E=V/d.

• Magnetic field lines.