Physics: Electric Charges and Fields

Electric Charges and Fields

• Electric charge is a fundamental property of matter, and it is measured in coulombs (C).
• There are two types of electric charges: positive and negative.
• Like charges repel each other, while opposite charges attract each other.
• Electric charge is quantized, meaning it comes in discrete packets (quanta) rather than being continuous.
• The smallest unit of electric charge is the elementary charge (e), which is approximately 1.6 × 10^-19 C.

Coulomb's Law

• Coulomb's Law states that the electric force between two point charges is proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them.
• The law is given by the equation: F = k * (q1 * q2) / r^2, where F is the electric force, k is Coulomb's constant, q1 and q2 are the magnitudes of the charges, and r is the distance between them.
• The value of Coulomb's constant (k) is approximately 9 × 10^9 N m^2 C^-2.

Electric Field

• An electric field is a region around a charged particle where the force of the charge can be detected.
• Electric field lines emerge from positive charges and enter negative charges.
• The electric field (E) at a point is defined as the force (F) per unit charge (q) at that point: E = F / q.
• Electric field is a vector quantity, and its unit is newton per coulomb (N/C) or volt per meter (V/m).

Electric Dipole

• An electric dipole consists of two point charges of equal magnitude but opposite signs, separated by a small distance.
• The electric dipole moment (p) is a measure of the strength of the dipole, given by p = q × d, where q is the magnitude of the charge and d is the distance between the charges.
• The electric field of a dipole decreases rapidly with distance, and its direction is along the line joining the charges.