# NCERT Solutions for Class 12 Physics

NCERT Solutions for Class 12 Physics in PDF form free download. NCERT solutions for CBSE and UP Board students of other subjects, Physics assignments, NCERT test papers, notes, study material, etc. in PDF form. In order to pursue student’s career in basic sciences and professional courses, they take up Physics as one of the subjects. To provide them sufficient background to meet the challenges of academic and professional streams, the Physics NCERT and other study material has been reformed, updated and designed to include information on all topics as per the latest CBSE syllabus 2018-19.

## NCERT Solutions for Class 12 Physics

### Solutions for Class 12 Physics – All Chapters

#### Chapter 15: Communication System

Due importance has been given to develop in the students, experimental and observation skills. Their learning experience would make them to appreciate the role of Physics towards the improvement of our society.

#### Important Derivations of class 12 Physics (Unit wise)

UNIT – 1 ELECTROSTATICS

Electric field intensity due to a dipole – behaviour of dipole in a uniform electric field. Gauss’s theorem and its applications to find field due to (1) infinitely long straight wire (2) uniformly charged infinite plane sheet (3) two parallel sheets and (4) uniformly charged thin spherical shell (inside and outside). Parallel plate capacitor with and without dielectric medium – energy stored in a capacitor.

UNIT – 2 CURRENT ELECTRICITY

Drift velocity and mobility and their relation with electric current. Kirchoff’s law – illustration by simple circuits – Wheatstone’s Bridge Metrebridge – Special case of Wheatstone bridge – Potentiometer – principle & comparing the emf of two cells.

UNIT – 3 EFFECTS OF ELECTRIC CURRENT

Biot-Savart law – Magnetic field due to an infinitely long current carrying straight wire and circular coil – Construction and working – Bar magnet as an equivalent solenoid – magnetic field lines. Ampere’s circuital law. Force on a moving charge in uniform magnetic field and electric field, forces between two parallel current carrying conductors . Torque experienced by a current loop in a uniform magnetic field-moving coil galvanometer – Conversion to ammeter and voltmeter

UNIT – 4 ELECTROMAGNETIC INDUCTION AND ALTERNATING CURRENT

Self-inductance of a long solenoid – mutual inductance of two long solenoids. AC generator – (Single phase, three phase). Transformer – Alternating current – measurement of AC – AC circuit with resistance – AC circuit with inductor – AC circuit with capacitor – LCR series circuit – Resonance and Q – factor: power in AC circuits.

UNIT–5 ELECTROMAGNETIC WAVES AND WAVE OPTICS

Wavefront and Huygen’s principle – Proving laws of Reflection, Refraction. Interference – Young’s double slit experiment and expression for fringe width – coherent source – interference of light. Formation of colours in thin films – Diffraction – differences between interference and diffraction of light. Uses of plane polarised light and Polaroids – rotatory polarisation.

UNIT – 6 ATOMIC PHYSICS

Hydrogen spectrum – energy level diagrams – sodium and mercury spectra – excitation and ionization potentials.

UNIT – 7 DUAL NATURE OF RADIATION AND MATTER – RELATIVITY

Einstein’s photo – electric equation – laws of photo – electric emission – work function. De–Broglie relation – De–Broglie wave length of an electron – electron microscope.

UNIT – 8 NUCLEAR PHYSICS

Nuclear Radii, masses, binding energy – Nuclear mass defect – binding energy. Radioactivity – alpha, beta and gamma radiations, Radioactive decay law – half life – mean life.

UNIT – 9 SEMICONDUCTOR DEVICES AND THEIR APPLICATIONS

Formation of P-N Junction – Barrier potential and depletion layer. – P-N Junction diode – Forward and reverse bias characteristics – diode as a rectifier – zener diode. Zener diode as a voltage regulator – LED. Transistor as an amplifier – Logic gates – NOT, OR, AND, EXOR using discret components – NAND and NOR gates as universal gates.

UNIT – 10 COMMUNICATION SYSTEMS