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Chapter 20 of 32
Revision Notes

Current ElectricityRevision Notes

NEET-UG · Physics

Quick revision notes for Current Electricity — key concepts, formulas, and definitions for NEET-UG Physics preparation.

Revision Notes — Current Electricity

Key concepts, formulas, and definitions from Current Electricity for NEET-UG Physics preparation.

Key Topics to Revise

1

Electric Current and Current Density

  • Electric current is the time rate of flow of charge through any cross-section of a conductor
  • Current is a scalar quantity with SI unit ampere (A) and CGS unit biot (Bi)
  • Conventional direction of current is opposite to the direction of electron flow
2

Drift Velocity and Mobility

  • Drift velocity is the average velocity acquired by free electrons due to applied electric field
  • Drift velocity is very small (~10⁻⁴ m/s) compared to thermal velocity (~10⁵ m/s)
  • Drift velocity is directly proportional to electric field: vd ∝ E
3

Ohm's Law and Resistance

  • Ohm's law states that current through a conductor is directly proportional to potential difference across it
  • V = IR is the mathematical form of Ohm's law where R is resistance
  • Ohm's law is valid only for ohmic conductors at constant temperature
4

Resistivity and Conductivity

  • Resistivity is an intrinsic property of materials, independent of shape and size
  • Resistivity varies with temperature, impurities, and mechanical stress
  • Conductivity is reciprocal of resistivity: σ = 1/ρ

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Key Concepts

Electric current is defined asCurrent density (J) is current perOhm's law states that the currentResistance (R) opposes current flowIn series

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Frequently Asked Questions

What topics are covered in Current Electricity for NEET-UG?

Current Electricity is an important chapter in NEET-UG Physics. It covers key concepts and formulas that are frequently tested in the exam. Key topics include: Electric Current and Current Density, Drift Velocity and Mobility, Ohm's Law and Resistance, Resistivity and Conductivity.

Current Electricity is a frequently tested chapter in NEET-UG Physics. Questions from this chapter appear regularly in previous year papers. There are 79 practice questions available for this chapter.

Start by understanding the core concepts, then solve practice questions. Focus on formulas and their applications. Use revision notes for quick review before the exam.