NEET Electrostatics and Current Electricity: Formula Sheet
Complete formula guide for Electrostatics and Current Electricity. Includes Coulombs law, capacitors, Ohms law, and circuit analysis.
Table of Contents
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Electrostatics and Current Electricity together contribute 8-10 questions (32-40 marks) in NEET Physics. These chapters are formula-heavy and highly scoring with practice.
Electrostatics
Coulombs Law
F = k × q1 × q2 / r²
- k = 9 × 10⁹ Nm²/C²
- Force is attractive (opposite charges) or repulsive (same charges)
Electric Field
E = F / q = kQ / r²
- Direction: Away from positive, towards negative
- Unit: N/C or V/m
Electric Potential
V = kQ / r
- Work done to bring unit charge from infinity
- Unit: Volt (V)
Capacitance
C = Q / V
- Unit: Farad (F)
- Parallel plate: C = ε₀A / d
Capacitors in Series and Parallel
Series: 1/C = 1/C1 + 1/C2 + 1/C3
Parallel: C = C1 + C2 + C3
Energy Stored in Capacitor
U = ½CV² = ½Q²/C = ½QV
Current Electricity
Ohms Law
V = IR
- V = Potential difference (V)
- I = Current (A)
- R = Resistance (Ω)
Resistance
R = ρL / A
- ρ = Resistivity
- L = Length
- A = Cross-sectional area
Resistors in Series and Parallel
Series: R = R1 + R2 + R3
Parallel: 1/R = 1/R1 + 1/R2 + 1/R3
Kirchhoffs Laws
Current Law (KCL): Sum of currents entering = Sum of currents leaving
Voltage Law (KVL): Sum of voltages in closed loop = 0
Power
P = VI = I²R = V²/R
- Unit: Watt (W)
Heating Effect
H = I²Rt
- Unit: Joule (J)
Important Formulas Table
| Quantity | Formula | Unit |
|---|---|---|
| Electric Force | F = kq1q2/r² | N |
| Electric Field | E = kQ/r² | N/C |
| Electric Potential | V = kQ/r | V |
| Capacitance | C = Q/V | F |
| Current | I = Q/t | A |
| Resistance | R = V/I | Ω |
| Power | P = VI | W |
High-Yield Topics
- Capacitor combinations (2-3 questions)
- Resistor networks (2-3 questions)
- Kirchhoffs laws (1-2 questions)
- Electric field and potential (2 questions)
Master these formulas and secure 32-40 marks in Physics!
Frequently Asked Questions
Common questions about this topic.
Electrostatics is more conceptual while Current Electricity is more numerical. Both are equally important. Practice 100+ numericals from each to master them.
Use Kirchhoffs laws systematically. Draw the circuit clearly, mark currents, apply KCL at junctions and KVL in loops. Practice 50+ circuit problems.
Capacitor questions are straightforward if you know series/parallel formulas and energy formula. Practice different combinations and you'll find them easy.
Yes, memorize all formulas in this chapter. Unlike Mechanics where you can derive, these formulas must be on your fingertips for quick solving.