CBSE Class 12 Physics Board Exam 2020: Most Important Topics and Derivations
CBSE Class 12 Physics Board Exam 2020 is scheduled to be held in March. Check important topics and derivations which can be asked in CBSE Class 12 Physics Board Exam 2020.
The syllabus of CBSE Class 12 Physics is vast. There are 15 chapters in NCERT textbooks of Class 12 Physics (Part I and Part II). Students preparing for CBSE Class 12 Physics board exam 2020 should know about important topics and derivations from these 15 chapters.
Although all the topics mentioned in latest CBSE Class 12th Physics syllabus 2020 are important. But, after the analysis of some previous year papers of CBSE Class 12th Physics, we have identified some important derivations, topics and questions which are extremely important for CBSE Class 12th Physics 2020 board exam.
CBSE Class 12 Physics Sample Paper 2020 (Issued by CBSE)
NCERT Based Notes for CBSE Class 12th Physics Board Exam 2020: All Chapters
Complete details related to important derivations and topics which can be asked in CBSE Class 12 board exam 2020 are given below:
Unit 1: Electrostatics
There are two chapters in this unit. Chapter: 1 is Electric Charges and Fields and Chapter: 2 is Electrostatic Potential and Capacitance. Important topics and derivations of these chapters are given below:
| Chapter 1: Electric Charges and Fields |
| Coulomb’s law in vector form (Agreement with Newton’s third law i.e. F12 = ‒F21). |
| Electric field intensity on Equatorial Line & Axial Line of an Electric Dipole. |
| Electric Field Intensity at various points due to a uniformly charged spherical shell (thin & thick both). |
| Electric filed intensity due to a thin infinite plane sheet of charge. |
| Application of Gauss theorem in calculation of electric field. |
| Chapter 2: Electrostatic Potential and Capacitance |
| Electric Potential due to a point charge. |
| Electric Potential on Axial Line & Equatorial Line of an Electric Dipole. |
| Capacitance of parallel plate capacitor (with or without dielectric medium). |
| Energy stored in a capacitor. |
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Unit 2: Current Electricity
There is only 1 chapter in this unit that is Current Electricity. Important concepts and derivations expected to be asked in CBSE Class 12 Physics board exam 2020 from this chapter are given below:
| Chapter ‒ 3: Current Electricity |
| Expression for drift velocity. |
| Relation between current and drift velocity. |
| Series and parallel connection of resistors (Derivations and Numerical Problems). |
| Kirchhoff’s laws and simple applications (Definition and Numerical Problems). |
| Potentiometer (Numerical are expected this year) |
Unit 3: Magnetic Effects of Current and Magnetism
There are two chapters in this unit of Class 12 Physics NCERT textbook. Name of these chapters are Moving Charges and Magnetism & Magnetism and Matter.
Important topics and derivations of these chapters are given below:
| Chapter – 4: Moving Charges and Magnetism |
| Application of Biot - Savart law (Calculation of magnetic field due to current carrying circular loop). |
| Ampere’s law and its applications (Magnetic field due to infinitely long straight wire; Straight and toroidal solenoids). |
| Force on a moving charge in uniform magnetic and electric fields (Numerical and Derication) |
| Cyclotron (Diagram, Theory and Derivation). |
| Force on a current-carrying conductor in a uniform magnetic field (Derivation and Numerical Problems). |
| Force between two parallel current-carrying conductors (including definition of ampere). |
| Torque experienced by a current loop in uniform magnetic field. |
| Moving coil galvanometer-its current sensitivity and conversion to ammeter and voltmeter. |
| Chapter ‒ 5: Magnetism and Matter |
| Current loop as a magnetic dipole and its magnetic dipole moment. |
| Magnetic dipole moment of a revolving electron. |
| Magnetic field intensity due to a magnetic dipole (bar magnet) along its axis and perpendicular to its axis. |
| Torque on a magnetic dipole (bar magnet) in a uniform magnetic field. |
| Properties of Para-, dia- and ferro - magnetic substances |
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Unit 4 Electromagnetic Induction and Alternating Current
There are two chapters in this unit of Class 12 Physics Syllabus. Name of these chapters are Electromagnetic Induction and Alternating Current.
Important topics and derivations of these chapters are given below:
| Chapter – 6: Electromagnetic Induction |
| Motional EMF or Induced EMF (Derivations and Numerical Problems). |
| Mutual Induction and Self Induction. |
| Chapter – 7: Alternating Current |
| Relation between rms and peak value of current & emf (Numerical Problems and Derivations). |
| Reactance, impedance & average power in series LCR, LR, CR or LR circuit. (Numerical Problems and Derivations). |
| Resonance in series LCR circuit. (Numerical Problems and Derivations). |
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Unit 5: Electromagnetic waves
There is only one chapter in this unit and that is Electromagnetic waves. Important topics and derivations of this chapter are given below:
| Displacement current (Basic Concept) |
| Characteristic and Properties of EM Waves |
| Electromagnetic spectrum |
Unit 6 Optics
There are 2 chapters in this unit. Name of these chapter are Ray Optics and Optical Instruments & Wave Optics.
Important topics of this chapter are given below:
| Chapter-9: Ray Optics and Optical Instruments |
| Total Internal Reflection (Definition and Numerical Problems) |
| Mirror Formula (Definition and Numerical Problems) |
| Lensmaker’s formula (Derivations and Numerical Problems) |
| Refraction and dispersion of light through a prism (Derivations and Numerical Problems) |
| Scattering of light (Blue colour of sky, reddish appearance of the sun at sunrise and sunset) |
| Microscopes and astronomical telescopes (Ray Diagram & Numerical Problems) |
| Refractive Index of a Prism and Condition for Minimum Deviation (Derivations and Numerical Problems) |
| Chapter-10: Wave Optics |
| Young double slit experiment (Derivations and Numerical Problems) |
| Diffraction using single slit (Derivations and Numerical Problems) |
| Polarisation (Definition and Numerical Problems) |
Unit 7: Dual Nature of Radiation and Matter
There is only one chapter in this unit. Name of the chapter is Dual Nature of Matter and Radiation. Important topics of this chapter are given below:
| Chapter-11: Dual Nature of Radiation and Matter |
| Dual nature of radiation |
| Photoelectric effect |
| Hertz and Lenard’s observations; |
| Einstein’s photoelectric equation-particle nature of light |
Unit 8: Atoms and Nuclei
There are two chapters in this unit. Name of these chapters are: Atoms and Nuclei. Important topics and derivations of this chapter are given below:
| Chapter-12: Atoms |
| Alpha-particle scattering experiment |
| Expression of radius (hydrogen like atoms) |
| Bohr model, energy levels, hydrogen spectrum (Including numerical problems) |
| Chapter-13: Nuclei |
| N = N0 e‒λt |
| Mass defect (Definition and Numerical Problems) |
| Binding energy per nucleon and its variation with mass number (Definition and Numerical Problems) |
| Nuclear fission & Nuclear fusion (Definition and Numerical Problems) |
Unit 9 Electronic Devices
Only one chapter is there in this unit. The name of this chapter is Semiconductor Electronics: Materials, Devices and Simple Circuits. Important topics of this chapter are given below:
| Chapter -14: Semiconductor Electronics: Materials, Devices and Simple Circuits |
| Energy bands in Conductors; Semiconductors and Insulators (qualitative ideas only) |
| Semiconductor diode: I-V characteristics in forward and reverse bias |
| Diode as a rectifier |
| Junction transistor: Common base transistor amplifier and Common emitter transistor amplifier |
These are some important derivations and topic from all the units of CBSE Class 12th Physics which are likely to be asked in coming 2020 board exam. While preparing for CBSE Class 12th Physics board exam 2020, students should give priority to the topics mentioned above.