Class 12 Physics
Chapter 1: Electric Charges and Fields
1. Coulomb's Law Derivation
Experimentally, electrostatic force between two point charges:
F proportional to q1q2
F proportional to 1/r^2
Therefore,
F = k (q1q2 / r^2)
In vacuum:
k = 1 / (4 pi epsilon_0)
So,
F = (1 / (4 pi epsilon_0)) (q1q2 / r^2)
2. Electric Field due to a Point Charge
Electric field is defined as:
E = F / q0
Using Coulomb's law,
E = (1 / (4 pi epsilon_0)) (q / r^2)
3. Principle of Superposition
If multiple charges are present,
Total Electric Field:
E = E1 + E2 + E3 + .... (vector sum)
4. Electric Dipole and Dipole Moment
Chapter 1: Electric Charges and Fields
1. Coulomb's Law Derivation
Experimentally, electrostatic force between two point charges:
F proportional to q1q2
F proportional to 1/r^2
Therefore,
F = k (q1q2 / r^2)
In vacuum:
k = 1 / (4 pi epsilon_0)
So,
F = (1 / (4 pi epsilon_0)) (q1q2 / r^2)
2. Electric Field due to a Point Charge
Electric field is defined as:
E = F / q0
Using Coulomb's law,
E = (1 / (4 pi epsilon_0)) (q / r^2)
3. Principle of Superposition
If multiple charges are present,
Total Electric Field:
E = E1 + E2 + E3 + .... (vector sum)
4. Electric Dipole and Dipole Moment
