CLASS 12 PHYSICS

Electrostatics, Current Electricity, Magnetic Effects of Current, Magnetism, Electromagnetic Induction, Alternating Currents, Optics, Electromagnetic Waves, Atoms and Nuclei, Electronic Devices, etc.

CHAPTER- 1 ELECTRIC CHARGE AND FIELDS

Electric charge is the basic physical property of matter that causes it to experience a force when kept in an electric or magnetic field.

CONTENTS

• INTRODUCTION
• ELECTRIC CHARGE
• CONDUCTORS AND INSULATORS
• CHARGING BY INDUCTION
• BASIC PROPERTIES OF ELECTRIC CHARGE
• COUL
• OMB’S LAW
• FORCES BETWEEN MULTIPLE CHARGES
• ELECTRIC FIELD LINES
• ELECTRIC FLUX
• ELECTRIC DIPOLE
• DIPOLE IN A UNIFORM EXTERNAL FIELD
• CONTINUOUS CHARGE DISTRIBUTION

1.14 GAUSS’S LAW

11.5 APPLICATIONS OF GAUSS’S LAW

Chapter 2: Electrostatic Potential And Capacitance

Electrostatic Potential The electrostatic potential at any point in an electric field is equal to the amount of work done per unit positive test charge or in bringing the unit positive test charge from infinity to that point, against the electrostatic force without acceleration.

CONTENTS

2.1 Introduction

2.2 Electrostatic Potential

2.3 Potential due to a Point Charge

2.4 Potential due to an Electric Dipole

2.5 Potential due to a System of Charges

2.6 Equipotential Surfaces

2.7 Potential Energy of a System of Charges

2.8 Potential Energy in an External Field

2.9 Electrostatics of Conductors

2.10 Dielectrics and Polarisation

2.11 Capacitors and Capacitance

2.12 The Parallel Plate Capacitor

2.13 Effect of Dielectric on Capacitance

2.14 Combination of Capacitors

2.15 Energy Stored in a Capacitor

CHAPTER- 3 CURRENT ELECTRICITY

Current electricity refers to the flow of electrons in an electric circuit from one place to another. Current electricity is the constant flow of electrons. Electrical energy is transported from one point to another in a circuit by the motion of electrons.

CONTENTS

3.1 Introduction

3.2 Electric Current

3.3 Electric Currents in Conductors

3.4 Ohm’s law

3.5 Drift of Electrons and the Origin of Resistivity 3.6 Limitations of Ohm’s Law

3.7 Resistivity of Various Materials

3.8 Temperature Dependence of Resistivity

3.9 Electrical Energy, Power

3.10 Cells, emf, Internal Resistance

3.11 Cells in Series and Parallel

3.12 Kirchhoff’s Rules

3.13 Wheatstone Bridge

CHAPTER- 4 MOVING CHARGES AND MAGNETISM

A stationary charge generates an electric field in its environment, and a moving charge generates a field in its environment that imposes a force on the moving charge.

CONTENTS

4.1 Introduction

4.2 Magnetic Force

4.3 Motion in a Magnetic Field

4.4 Magnetic Field due to a Current Element, Biot-Savart Law

4.5 Magnetic Field on the Axis of a Circular Current Loop

4.6 Ampere’s Circuital Law

4.7 The Solenoid

4.8 Force between Two Parallel Currents, the Ampere

4.9 Torque on Current Loop, Magnetic Dipole

4.10 The Moving Coil Galvanometer

CHAPTER- 5 MAGNETISM AND MATTER

The magnetism of matter is the force exerted by magnets when they attract or repulse each other. Magnetic moments and the electric currents of basic particles give rise to a magnetic field, which acts on other magnetic and current moments.

CONTENTS

5.1 Introduction

5.2 The Bar Magnet

5.3 Magnetism and Gauss’s Law

5.4 Magnetisation and Magnetic Intensity

5.5 Magnetic Properties of Materials

CHAPTER- 6 ELECTROMAGNETIC INDUCTION

Electromagnetic Induction is a current produced because of voltage production (electromotive force) due to a changing magnetic field.

CONTENTS

6.1 Introduction

6.2 The Experiments of Faraday and Henry

6.3 Magnetic Flux

6.4 Faraday’s Law of Induction

6.5 Lenz’s Law and Conservation of Energy

6.6 Motional Electromotive Force

6.7 Inductance

6.8 AC Generator

CHAPTER- 7 ALTERNATING CURRENT

CONTENTS

7.1 Introduction

7.2 AC Voltage Applied to a Resistor

7.3 Representation of AC Current and Voltage by Rotating Vectors — Phasors

7.4 AC Voltage Applied to an Inductor

7.5 AC Voltage Applied to a Capacitor

7.6 AC Voltage Applied to a Series LCR Circuit

7.7 Power in AC Circuit: The Power Factor

CHAPTER- 8 ELECTROMAGNETIC WAVES

Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field. In other words, EM waves are composed of oscillating magnetic and electric fields.

CONTENTS

8.1 Introduction

8.2 Displacement Current

8.3 Electromagnetic Waves

8.4 Electromagnetic Spectrum

CHAPTER- 9 RAY OPTICS AND OPTICAL INSTRUMENTS

Ray Optics and Optical Instruments is a branch of physics that study the behaviour and properties of light. In Ray Optics, also known as Geometrical Optics, the light travels in a straight line and states that there is an image for each and every object.

CONTENTS

9.1 Introduction

9.2 Reflection of Light by Spherical Mirrors

9.3 Refraction

9.4 Total Internal Reflection

9.5 Refraction at Spherical Surfaces and by Lenses

9.6 Refraction through a Prism

9.7 Optical Instruments

CHAPTER- 10 WAVE OPTICS

Wave Optics Describes the connection between waves and rays of light.

CONTENTS

10.1 Introduction

10.2 Huygens Principle

10.3 Refraction and Reflection of Plane Waves using Huygens Principle

10.4 Coherent and Incoherent Addition of Waves

10.5 Interference of Light Waves and Young’s Experiment

10.6 Diffraction

10.7 Polarisation

CHAPTER-11 DUAL NATURE OF RADIATION AND MATTER

The dual nature of radiation is considered as wave nature and particle nature in the presence of light emission through electrons.

CONTENTS

11.1 Introduction

11.2 Electron Emission

11.3 Photoelectric Effect

11.4 Experimental Study of Photoelectric Effect

11.5 Photoelectric Effect and Wave Theory of Light

11.6 Einstein’s Photoelectric Equation: Energy Quantum of Radiation

11.7 Particle Nature of Light: The Photon

11.8 Wave Nature of Matter

CHAPTER- 12 ATOMS

An atom consists of a small and massive central core in which the entire positive charge and almost the whole mass of the atom are concentrated.

CONTENTS

12.1 Introduction

12.2 Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom

12.3 Atomic Spectra

12.4 Bohr Model of the Hydrogen Atom

12.5 The Line Spectra of the Hydrogen Atom

12.6 DE Broglie’s Explanation of Bohr’s Second Postulate of Quantisation

CHAPTER- 13 NUCLEI

The overall dimensions of a nucleus are much smaller than those of an atom. Experiments on the scattering of α-particles demonstrated that the radius of a nucleus was smaller than the radius of an atom by a factor of about 104. This means the volume of a nucleus is about 10–12 times the volume of the atom.

CONTENTS

13.1 Introduction

13.2 Atomic Masses and Composition of Nucleus

13.3 Size of the Nucleus

13.4 Mass-Energy and Nuclear Binding Energy

13.5 Nuclear Force

13.6 Radioactivity

13.7 Nuclear Energy

CHAPTER- 14 SEMICONDUCTOR ELECTRONICS: MATERIALS, DEVICES AND SIMPLE CIRCUITS

There is a whole new world of materials other than metals and non-metals, popularly known as semiconductor materials. They define the new cutting-edge technologies used in today’s world of electronic devices.

CONTENTS

14.1 Introduction

14.2 Classification of Metals, Conductors and Semiconductors

14.3 Intrinsic Semiconductor

14.4 Extrinsic Semiconductor