**ISC Class 12 Physics Syllabus 2023 PDF Download: Check Revised Class 12th Physics Syllabus** – ISC Class 12 Physics (Code: 861) syllabus introduces many important topics. In this article, you will find the latest and revised ISC Class 12 Physics Syllabus 2023 in pdf format.

**ISC Board Class 12 Physics Exam Pattern 2023**

- Papers – Two
- Paper 1: Theory – 80 marks
- Exam Duration – 3 Hours
- Project Work – 20 Marks

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**ISC Board Class 12 Physics Syllabus 2023**

**PAPER I -THEORY- 70 Marks**

**Note: **(i) Unless otherwise specified, only S. I. Units are to be used while teaching and learning, as well as for answering questions.

(ii) All physical quantities to be defined as and when they are introduced along with their units and dimensions.

(iii) Numerical problems are included from all topics except where they are specifically excluded or where only qualitative treatment is required.

**Electrostatics**

(i) Electric Charges and Fields

Electric charges; conservation and quantisation of charge, Coulomb’s law; 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 field.

Electric flux, Gauss’s theorem in Electrostatics and its applications to find field due to infinitely long straight wire, uniformly charged infinite plane sheet and uniformly charged thin spherical shell.

(a) Coulomb’s law, S.I. unit of charge; permittivity of free space and of dielectric medium. Frictional electricity, electric charges (two types); repulsion and attraction; simple atomic structure – electrons and ions; conductors and insulators; quantization and conservation of electric charge; Coulomb’s law in vector form; (position coordinates r_{1}, r_{2 }not necessary). Comparison with Newton’s law of gravitation; Superposition principle.

(b) Concept of electric field and its intensity; examples of different fields; gravitational, electric and magnetic; Electric field due to a point charge = /q_{0} (q_{0} is a test charge); for a group of charges (superposition principle); a point charge q in an electric

field experiences an electric force _{E}_{ }= q Intensity due to a continuous distribution of charge i.e. linear, surface and volume. rr

(c) Electric lines of force: A convenient way to visualize the electric field; properties of lines of force; examples of the lines of force due to (i) an isolated point charge (+ve and – ve); (ii) dipole, (iii) two similar charges at a small distance;(iv) uniform field between two oppositely charged parallel plates.

(d) Electric dipole and dipole moment; derivation of the at a point, (1) on the axis (end on position) (2) on the perpendicular bisector (equatorial i.e. broad side on position) of a dipole, also for r>> 2l (short dipole); dipole in a uniform electric field; net force zero, torque on an electric dipole: = x and its derivation.

Applications: Obtain expression for due to 1. an infinite line of charge, 2. a uniformly charged infinite plane thin sheet, 3. a thin hollow spherical shell (inside, on the surface and outside). Graphical variation of E vs r for a thin spherical shell. E

(ii) Electrostatic Potential, Potential Energy and Capacitance

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, energy stored in a capacitor.

(b) Capacitance of a conductor C = Q/V; obtain the capacitance of a parallel-plate capacitor (C = ∈_{0}A/d) and equivalent capacitance for capacitors in series and parallel combinations. Obtain an

expression for energy stored (U = 1/2CV^{2} = 1/2 QV = 1/2Q^{2}/c) and energy density.

(c) Dielectric constant K = C’/C; this is also called relative permittivity K = ∈r = ∈/∈o; elementary ideas of polarization of matter in a uniform electric field qualitative discussion; induced surface charges weaken the original field; results in reduction in and hence, in pd, (V); for charge remaining the same Q = CV = C’ V’ = K. CV’; V’ = V/K; and; if the Capacitor is kept connected with the source of emf, V is kept constant V = Q/C = Q’/C’ ; Q’=C’V = K. CV= K. Q increases; For a parallel plate capacitor with a dielectric in between, C’ = KC = K.∈o . A/d = ∈r .∈o .A/d. Then C’’=∈_{0}A/(d/∈_{r}); for a capacitor partially filled dielectric, capacitance, C’ =∈oA/(d-t + t/∈r).

**Current Electricity**

Mechanism of flow of current in conductors. Mobility, drift velocity and its relation with electric current; Ohm’s law and its proof, resistance and resistivity and their relation to drift velocity of electrons; V-I characteristics (linear and non-linear), electrical energy and power, electrical resistivity and conductivity. Temperature dependence of resistance and resistivity.

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, to compare emf of two cells; to measure internal resistance of a cell.

(a) Free electron theory of conduction; acceleration of free electrons, relaxation time τ; electric current I = Q/t; concept of drift velocity and electron mobility. Ohm’s law, current density J = I/A; experimental verification, graphs and slope, ohmic and non-ohmic conductors; obtain the relation I=v_{d}enA. Derive σ= ne^{2}τ/m and ρ= m/ne^{2}; effect of temperature on resistivity and resistance of conductors and semiconductors and graphs. Resistance R= V/I; resistivity ρ, given by R = ρ.l/A; conductivity and conductance; Ohm’s law as = σ

(b) Electrical energy consumed in time t is E=Pt= VIt; using Ohm’s law E = V^{2/}Rt = I^{2}Rt. Potential difference V = P/ I; P = V I; Electric power consumed P = VI = V^{2} /R = I^{2} R; commercial units; electricity consumption and billing.

(c) The source of energy of a seat of emf (such as a cell) may be electrical, mechanical, thermal or radiant energy. The emf of a source is defined as the work done per unit charge to force them to go to the higher point of potential (from -ve terminal to +ve terminal inside the cell) so, ε= dW /dq; but dq = Idt; dW = εdq = εIdt . Equating total work done to the work done across the external resistor R plus the work done across the internal resistance r; εIdt=I^{2}R dt + I^{2}rdt; ε=I (R + r); I=ε/( R + r ); also IR +Ir = εor V=ε- Ir where Ir is called the back emf as it acts against the emf ε; V is the terminal pd. Derivation of formulae for combination for identical cells in series, parallel and mixed grouping. Parallel combination of two cells of unequal emf. Series combination of n cells of unequal emf.

(d) Statement and explanation of Kirchhoff’s laws with simple examples. The first is a conservation law for charge and the 2nd is law of conservation of energy. Note change in potential across a resistor ΔV=IR<0 when we go ‘down’ with the current (compare with flow of water down a river), and ΔV=IR>0 if we go up against the current across the resistor. When we go through a cell, the -ve terminal is at a lower level and the +ve terminal at a higher level, so going from -ve to +ve through the cell, we are going up and

ΔV=+εand going from +ve to -ve terminal through the cell, we are going down, so ΔV = -ε. Application to simple circuits. Wheatstone bridge; right in the beginning take Ig=0 as we consider a balanced bridge, derivation of R_{1}/R_{2} = R_{3}/R_{4} [Kirchhoff’s law not necessary]. Metre bridge is a modified form of Wheatstone bridge, its use to measure unknown resistance. Here R_{3} = l_{1}ρand R_{4}=l_{2}ρ; R_{3}/R_{4}=l_{1}/l_{2}. Principle of Potentiometer: fall in potential ΔV αΔl; auxiliary emf ε1 is balanced against the fall in potential V_{1} across length l_{1}. ε_{1} = V_{1} =Kl_{1} ; ε_{1}/ε_{2} = l_{1}/l_{2}; potentiometer as a voltmeter. Potential gradient and sensitivity of potentiometer. Use of potentiometer: to compare emfs of two cells, to determine internal resistance of a cell.