CBSE-2018 Course Structure for Physics of XII
One Paper time is 3 hours and 70 marks
Magnetic effect of current & Magnetism
Electromagnetic Induction andAlternating current
Dual Nature of Matter
Atoms and Nuclei
Unit I: Electrostatics (Periods 25)
Electric Charges; Conservation of charge, Coulomb's law-force between two point charges, forces between multiple charges; superposition principle and continuous charge distribution.
Electric field, electric field due to a point charge, electric field lines, electric dipole, electric field due to a dipole, torque on a dipole in uniform electric fleld.
Electric flux, statement of Gauss's theorem and its applications to find field due to infinitely long straight wire, uniformly charged infinite plane sheet and uniformly charged thin spherical shell (field inside and outside).
Electric potential, potential difference, electric potential due to a point charge, a dipole and system of charges; equipotential surfaces, electrical potential energy of a system of two point charges and of electric dipole in an electrostatic field.
Conductors and insulators, free charges and bound charges inside a conductor. Dielectrics and electric polarisation, capacitors and capacitance, combination of capacitors in series and in parallel, capacitance of a parallel plate capacitor with and without dielectric medium between the plates, energy stored in a capacitor. Van de Graaff generator.
Unit II: Current Electricity (Periods 22)
Electric current, flow of electric charges in a metallic conductor, drift velocity, mobility and their relation with electric current; Ohm's law, electrical resistance, V-I characteristics (linear and non-linear), electrical energy and power, electrical resistivity and conductivity. Carbon resistors, colour code for carbon resistors; series and parallel combinations of resistors; temperature dependence of resistance.
Internal resistance of a cell, potential difference and emf of a cell, combination of cells in series and in parallel.
Kirchhoff's laws and simple applications. Wheatstone bridge, metre bridge.
Potentiometer-principle and its applications to measure potential difference and for comparing emf of two cells; measurement of internal resistance of a cell.
Unit III: Magnetic Effects of Current and Magnetism (Periods 25)
Concept of magnetic field, Oersted's experiment.
Biot-Savart law and its application to current carrying circular loop. Ampere's law and its applications to infinitely long straight wire. Straight and toroidal solenoids, Force on a moving charge in uniform magnetic and electric fields. Cyclotron.
Force on a current-carrying conductor in a uniform magnetic field. Force between two parallel current-carrying conductors-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.
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; bar magnet as an equivalent solenoid, magnetic field lines; Earth's magnetic field and magnetic elements. Para-, dia-and ferro-magnetic substances, with examples. Electromagnets and factors affecting their strengths. Permanent magnets.
Unit IV: Electromagnetic Induction and Alternating Currents (Periods 20)
Electromagnetic induction; Faraday's laws, induced emf and current; Lenz's Law, Eddy currents. Self and mutual induction.
Alternating currents, peak and rms value of alternating current/voltage; reactance and impedance; LC oscillations (qualitative treatment only), LCR series circuit, resonance; power inAC circuits, wattless current.
AC generator and transformer.
Unit V: Electromagnetic waves (Periods 4)
Need for displacement current, Electromagnetic waves and their characteristics (qualitative ideas only). Transverse nature of electromagnetic waves.
Electromagnetic spectrum (radio waves, microwaves, infrared, visible, ultraviolet, X-rays, gamma rays) including elementary facts about their uses.
Unit VI: Optics (Periods 30)
Reflection of light, spherical mirrors, mirror formula. Refraction of light, total internal reflection and its applications, optical fibres, refraction at spherical surfaces, lenses, thin lens formula, lens-maker's formula. Magnification, power of a lens, combination of thin lenses in contact, combination of a lens and a mirror. Refraction and dispersion of light through a prism.
Scattering of light-blue colour of sky and reddish apprearance of the sun at sunrise and sunset.
Optical instruments: Human eye, image formation and accommodation, correction of eye defects (myopia, hypermetropia) using lenses. Microscopes and astronomical telescopes (reflecting and refracting) and their magnifying powers.
Wave optics: Wave front and Huygen's principle, reflection and refraction of plane wave at a plane surface using wave fronts. Proof of laws of reflection and refraction using Huygen's principle. Interference, Young's double slit experiment and expression for fringe width, coherent sources and sustained interference of light. Diffraction due to a single slit, width of central maximum. Resolving power of microscopes and astronomical telescope. Polarisation, plane polarised light, Brewster's law, uses of plane polarised light and Polaroids.
Unit VII: Dual Nature of Matter and Radiation (Periods 8)
Dual nature of radiation. Photoelectric effect, Hertz and Lenard's observations; Einstein's photoelectric equation-particle nature of light. Matter waves-wave nature of particles, de Broglie relation. Davisson-Germer experiment (experimental details should be omitted; only conclusion should be explained).
Unit VIII: Atoms & Nuclei (Periods 18)
Alpha-particle scattering experiment; Rutherford's model of atom; Bohr model, energy levels, hydrogen spectrum.
Composition and size of nucleus, atomic masses, isotopes, isobars; isotones. Radioactivity-alpha, beta and gamma particles/rays and their properties; radioactive decay law. Mass-energy relation, mass defect; binding energy per nucleon and its variation with mass number; nuclear fission, nuclear fusion.
Unit IX: Electronic Devices (Periods 18)
Energy bands in solids (Qualitative ideas only) conductor, insulator and semiconductor; semiconductor diode-I-V characteristics in forward and reverse bias, diode as a rectifier; I-V characteristics of LED, photodiode, solar cell, and Zener diode; Zener diode as a voltage regulator. Junction transistor, transistor action, characteristics of a transistor, transistor as an amplifier (common emitter configuration) and oscillator. Logic gates (OR, AND, NOT, NAND and NOR). Transistor as a switch.
Unit X: Communication Systems (Periods 10)
Elements of a communication system (block diagram only); bandwidth of signals (speech, TV and digital data); bandwidth of transmission medium. Propagation of electromagnetic waves in the atmosphere, sky and space wave propagation. Need for modulation. Production and detection of an amplitude-modulated wave.
Practicals- (Total Periods 60)
The record, to be submitted by the students, at the time of their annual examination, has to include
- Record of at least 15 Experiments [with a minimum of 7 from section A and 8 from section B], to be performed by the students.
- Record of at least 6 Activities [with a minimum of 3 each from section A and section B], to be demonstrated by the teachers.
- The Report of the project, to be carried out by the students.
Evaluation Scheme in Total Periods: 60
Two experiments one from each section
8 + 8 Marks
Practical record [experiments & activities]
Viva on experiments & project 8 + 8 Marks
Experiments (Any 7 experiments out of the following to be performed by the students)
- To determine resistance per cm of a given wire by plotting a graph of potential difference versus current.
- To find resistance of a given wire using metre bridge and hence determine the resistively (specific resistance) of its material
- To verify the laws of combination (series/parallel) of resistances using a metre bridge.
- To compare the emf of two given primary cells using potentiometer.
- To determine the internal resistance of given primary cell using potentiometer.
- To determine resistance of a galvanometer by half-deflection method and to find its figure of merit.
- To convert the given galvanometer (of known resistance and figure of merit) into an ammeter and voltmeter of desired range and to verify the same.
- To find the frequency of the a. c. Mains with a sonometer.
Activities (For the purpose of demonstration only)
- To measure the resistance and impedance of an inductor with or without iron core.
- To measure resistance, voltage (AC/DC), current (AC) and check continuity of a given circuit using multimeter.
- To assemble a household circuit comprising three bulbs, three (on/off) switches, a fuse and a power source.
- To assemble the components of a given electrical circuit.
- To study the variation in potential drop with length of a wire for a steady current.
- To draw the diagram of a given open circuit comprising at least a battery, resistor/rheostat, key, ammeter and voltmeter. Mark the components that are not connected in proper order and correct the circuit and also the circuit diagram.
(Any 8 experiments out of the following to be performed by the students)
- To find the value of v for different values of u in case of a concave mirror and to find the focal length.
- To find the focal length of a convex mirror, using a convex lens.
- To find the focal length of a convex lens by plotting graphs between u and v or between 1/u and 1/v.
- To find the focal length of a concave lens, using a convex lens.
- To determine angle of minimum deviation for a given prism by plotting a graph between angle of incidence and angle of deviation.
- To determine refractive index of a glass slab using a travelling microscope.
- To find refractive index of a liquid by using concave mirror, convex lens and plane mirror.
- To draw the characteristic curve of a zener diode and to determine its reverse break down voltage.
- To study the characteristic of a common-emitter npn or pnp transistor and to find out the values of current and voltage gains.
Activities (For the purpose of demonstration only)
- To identify a diode an LED, a transistor, an IC, a resistor and a capacitor from a mixed collection of such items.
- Use of multimeter to
- identify base of transistor
- distinguish between npn and pnp type transistors
- see the unidirectional flow of current in case of a diode and an LED
- check whether a given electronic component (e. g. Diode, transistor or IC) is in working order.
- To study effect of intensity of light (by varying distance of the source) on an L. D. R.
- To observe refraction and lateral deviation of a beam of light incident obliquely on a glass slab. To observe polarization of light using two Polaroids.
- To observe diffraction of light due to a thin slit.
- To study the nature and size of the image formed by a convex lens, concave mirror, on a screen by using a candle and a screen (for different distances of the candle from the lens/mirror).
- To obtain a lens combination with the specified focal length by using two lenses from the given set of lenses.
Suggested Investigatiory Projects class XII
- To study various factors on which the internal resistance/emf of a cell depends.
- To study the variations, in current flowing, in a circuit containing a LDR, because of a variation.
- in the power of the incandescent lamp, used to ‘illuminate’ the LDR (keeping all the lamps at a fixed distance).
- in the distance of a incandescent lamp (of fixed power) used to ‘illuminate’ the LDR.
- To find the refractive indices of (a) water (b) oil (transparent) using a plane mirror, a equiconvex lens (made from a glass of known refractive index), and an adjustable object needle.
- To design an appropriate logic gate combination for a given truth table. To investigate the relation between the ratio of
- output and input voltage
- number of turns in the secondary coil and primary coil of a self designed transformer.
- To investigate the dependence of the angle of deviation on the angle of incidence, using a hollow prism filled, one by one, with different transparent fluids.
- To estimate the charge induced on each one of the two identical styro foam (or pith) balls suspended in a vertical plane by making use of Coulomb's law.
- To set up a common base transistor circuit and to study its input and output characteristic and to calculate its current gain.
- To study the factor on which the self inductance of a coil depends by observing the effect of this coil, when put in series with a resistor/(bulb) in a circuit fed up by an a. c. Source of adjustable frequency.
- To construct a switch using a transistor and to draw the graph between the input and output voltage and mark the cut-off, saturation and active regions.
- To study the earth's magnatic field using a tangent galvanometer.