ICSE Board Physics Syllabus for Class 12

There will be two papers in the subject.
Paper I:  Theory -  3 hour  ... 70 marks
Paper II:  Practical -  3 hours ...  20 marks
Project Work   ...   7 marks
Practical File   ...  3 marks

PAPER I -THEORY- 70 Marks

Paper I shall be of 3 hours duration and be divided
into two parts.

Part I (20 marks): This part will consist of
compulsory short answer questions, testing knowledge, application and skills relating to elementary/fundamental aspects of the entire syllabus.

Part II (50 marks):  This part will be divided into  three Sections A, B and C. There shall be  three questions in Section A (each carrying 9 marks) and candidates are required to answer two questions from this Section. There shall be three questions in Section B (each carrying 8 marks) and candidates are
required to answer  two questions from this Section. There shall be  three questions in Section C (each carrying 8 marks) and candidates are required to answer  two questions from this Section. Therefore, candidates are expected to answer  six  questions in Part 2.
ote: Unless otherwise specified, only S. I. units are to be used while teaching and learning, as well as for answering questions.

1.   Electrostatics

(i) Coulomb's law, S.I. unit of charge; permittivity of free space. Review of electrostatics covered in Class X.
Frictional electricity, electric charge (two types); repulsion and attraction; simple atomic structure - electrons and protons as electric charge carriers; conductors, insulators; quantisation of electric charge; conservation of charge; Coulomb's law (in free space only); vector form; (position coordinates r1, r2 not necessary); SI unit of charge; Superposition principle; simple numerical problems.

(ii) Concept of electric field E = F/qo; Gauss' theorem and its applications.Action at a distance versus field concept; examples of different fields;  temperature and pressure (scalar); gravitational, electric and magnetic (vector field); definition  E F q = / o r r.Electric  field  due  to  a point charge;  E
r for a group of charges (superposition); A point charge q in an electric field  E r experiences an electric force  F qE E =r r.

Gauss’ theorem: the flux of a vector field; Q=VA for velocity vector  V A,r r the area  vector, for uniform flow of a liquid. Similarly for electric field  Er, electric flux  φE  = EA for  E A r r and  φ E = ⋅ E A r r for uniform  E r. For  non-uniform field  φE  = ∫dφ = ∫ E dA .r r. Special
cases for  θ = 0°, 90° and 180°. Examples, 
calculations. Gauss’ law, statement: φE =q/∈0 or  φ E = ∫ 0 q E dA ⋅ = ∈ r r where  φE is for a closed surface; q is the net charge enclosed,
∈o is the permittivity of free space. Essential properties of a Gaussian surface.  Applications: 1. Deduce Coulomb's law from the Gauss’ law and certain symmetry
considerations (=o proof required); 2 (a).  An excess charge placed on an isolated conductor resides on the outer surface;  (b) ]E r
=0 inside a cavity in an isolated conductor; (c) E = σ/∈0 for a point outside; 3.  E r due to an infinite line of charge, sheet of charge, spherical shell of charge(inside and outside); hollow spherical conductor. [Experimental test of coulomb’s law not included].

(iii) Electric dipole; electric field at a point on the axis and perpendicular bisector of a dipole; electric dipole moment; torque on a dipole in a uniform electric field. Electric dipole and dipole moment; with unit; derivation of the  E r at any point, (a) on the axis (b) on the perpendicular bisector of the
dipole, for r>> 2l. [ E r due to continuous distribution of charge, ring of charge, disc of charge etc not included]; dipole in uniform E r electric field; net force zero, torque τ = × p E r r r

(iv) 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 an isolated point charge (+ve and - ve); dipole, two similar charges at a small distance; uniform field between two oppositely charged parallel plates.

(v) Electric potential and potential energy; potential due to a point charge and due to a dipole; potential energy of an electric dipole in an electric field. Van de Graff generator. Brief review of conservative forces of which gravitational force and electric forces are examples; potential, pd and potential energy are definedonly in a conservative field; electric potential at a point; definition VP=W/q0;  hence VA -VB = WBA/  q0  (taking q0 from B to A) = (q/4πε0)(1/rA - 1/rB);derive this equation; also VA = q/4πε0 .1/rA ; for q>0, VA>0 and for q<0, VA < 0. For a collection of charges   V = sum of the potential due to each charge; potential due to a dipole on its axial line and equatorial line; also at any point for r>>d. Potential energy of a point charge (q) in an electric field  E, placed at a point P where potential is V, is given by U =qV and ∆U =q (VA-VB) . The electrostatic potential energy of a system of two charges = work done W21=W12 inassembling the system;U12 or U21 = (1/4πε0 ) q1q2/r12.For a system of
3 charges U123  = U12  + U13  + U23=01 4πε 1 2 1 3 2 3 12 13 23 ( ) q q q q q q r r r + + . For a dipole  in a uniform electric field, the electric potential energy UE = - p r . E r special case for φ =0, 90 0 and 180 0

Van de Graff Generator. Potential inside a charged spherical shell is uniform. A small conducting sphere of radius r and carrying charge q is located inside a large shell of radius R that carries charge Q.  The potential difference between the spheres, V(R) – V(r) = (q/4πεo) (1/R – 1/r) is independent of Q.  If the two are connected, charge always flows from the inner sphere to the outer sphere, raising its potential.  Sketch of a very simple Van de Graff Generator, its working and use. (vi) Capacitance of a conductor C = Q/V, the farad; capacitance of a parallel-plate capacitor; C = K∈0A/d capacitors in series and parallel combinations; energy U = 1/2CV 2 = 2 1 1 2 2 Q QV C = . Self-explanatory. Combinations of capacitors in series and parallel; effective capacitance and charge (vii) Dielectrics (elementary ideas only); permittivity and relative permittivity of a dielectric (∈r =  ∈/∈o). Effects on pd, charge and capacitance.
Dielectric constant Ke = C'/C; this is also called relative permittivity Ke =  ∈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  E r and hence, in pd, (V); for charge remaining the same Q = CV = C' V' = Ke. CV' ; V' = V/Ke; and e E E K′ = ; if the C is kept connected with the source of emf, V is kept constant V = Q/C = Q'/C' ; Q'=C'V = Ke. CV= Ke . Qincreases; For a parallel plate capacitor with a dielectric in between C' = KeC = Ke .∈o . A/d =   ∈ .∈o .A/d. Then, 0 r A C d ∈′ =      ∈ ;
extending this to a partially filled capacitor  C' =∈oA/(d-t + t/∈r).Spherical and cylindrical capacitors (qualitative only).

2.   Current Electricity

(i) Steady currents; sources of current, simple cells, secondary cells. Sources of emf: Mention: Standard cell, solar cell, thermo-couple and battery, etc. simple cells, acid/alkali cells - qualitative  description.

(ii) Potential difference as the power supplied divided by the current; Ohm's law and its limitations; Combinations of resistors in series and parallel; Electricenergy and power. Definition of pd, V = P/ I; P = V I;electrical energy consumed in time t is E=Pt= VIt; using ohm’s law                                    E = VIt =  t R V 2 = I 2 Rt. Electric power consumed P = VI = V 2 /R = I 2 R ; SI units;
commercial units; electricity consumption and billing. Ohm's law, current density  σ = I/A; experimental verification, graphs and slope,  resistors; examples; deviations. Derivation of formulae for combination of resistors in series and parallel; special case of n identical resistors; Rp = R/n. (iii)Mechanism of flow of current in metals, drift velocity of charges. Resistance and resistivity and their relation to drift velocity of electrons; description of resistivity and conductivity based on electron theory; effect of temperature on resistance, colour coding of resistance.  Electric current I = Q/t; atomic view of               flow of electric current in metals; I=vdena. Electron theory of conductivity; acceleration                        of electrons, relaxation time  τ ;                derive σ = ne2 τ/m and ρ = m/ne 2 τ ; effect of temperature on resistance. Resistance R= V/I for ohmic substances; resistivity ρ, given by R =  ρ.l/A; unit of  ρ is  Ω.m;conductivity σ=1/ρ ; Ohm’s law as  J r =  σ E r ; colour coding of resistance. 
(iv) Electromotive force in a cell; internal resistance and back emf. Combination of cells in series and parallel. 

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=I2dt + Irdt; ε =I (R + r); I=ε/( R + r ); also IR +Ir =  ε or V=ε- Ir where Ir is called the back emf as it acts against the emf  ε; V is the terminal pd. Derivation of formula for combination of cells in series, parallel and mixed grouping.  (v) Kirchhoff's laws and their simple applications to circuits with resistors and sources of emf;  bridge, metre-bridge and potentiometer; use for comparison of emf and determination of internal resistance of sources of current; use of resistors (shunts and multipliers) in ammeters and voltmeters. Statement and explanation with simple examples. The first is a conservation law for charge and the 2nd is law of conservation of energyote change in potential across a resistor  ∆V=IR<0 when we go ‘down’ with the current (compare with flow of water down a river), and ∆V=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 ∆V=+ε and going from +ve to -ve terminal through the cell we are going down, so  ∆V = -ε. Application to simple circuits. Wheatstone bridge; right in the beginning take Ig=0 as we consider a balanced bridge, derivation of R1/R2 = R3/R4 is simpler [Kirchhoff’s law not necessary].
Metre bridge is a modified form of Wheatstone bridge. Here R2 = l1p and R4 =l2 p; R1/R3   = l1/l2 .  Potentiometer: fall in potential ∆V α ∆l - conditions; auxiliary emf ε1 is balanced against the fall in potential across length l1 .  ε1 = V1 =Kl1 ; ε1/ε2 = l1/l2;  as a voltmeter. Potential gradient; comparison of emfs; determination of internal resistance of a cell. Conversion of galvanometer to ammeter and voltmeter and
their resistances.
(vi) Heating effect of a current (Joule's law). Flow of electric charge (current) in a conductor causes transfer of energy from the source of electricity (may be a cell or dynamo), to the conductor (resistor), as  internal energy associated with the vibration of atoms and observed as increase in From the definition of pd,      V=W/q; W =  ∆U = qV = VIt.  The rate of energy transfer  ∆U/t = VI or power P = VI = I2R=V2/R using Ohm's law.  This is Joule,s law.  This energy transfer is called
Joule heating.  SI unit of power. Experimental verification of Joule’s law. (vii)Thermoelectricity; Seebeck effect; measurement of thermo emf; its variation with temperature. Peltier effect. Discovery of Seebeck effect. Seebeck series; Examples with different pairs of metals (for easy recall remember - hot cofe and ABC - from copper to iron at the hot junction and from antimony to bismuth at the cold junction for current directions in thermocouple); variation of thermo emf with temperature differences, graph; neutral temperature, temperature of inversion; slope: thermoelectric power ε = αφ + 1/2β φ 2  (no derivation), S = dε/dφ =  α+βφ . The comparison of Peltier effect and Joule effect.

3.   Magnetism

(i) Magnetic field  Br, definition from magnetic force on a moving charge; magnetic field lines. Superposition of magnetic fields; magnetic field and magnetic flux density; the earth's magnetic field; Magnetic field of a magnetic dipole; tangent law.
Magnetic field represented by the symbol  B now defined by the equation  F q V = or r x  B\r(which comes later under subunit 4.2;  Br is
not to be defined in terms of force acting on a
unit pole, etc; note the distinction of  Brfrom Eris that rforms closed loops as there are no magnetic monopoles, whereas  Elines
start from +ve charge and end on -ve charge. 
Magnetic field lines due to a magnetic dipole (bar magnet). Magnetic field in end-on and broadside-on positions (=o derivations).
Magnetic flux  φB = B r. A r = BA for B uniform and  Br A; i.e. area held perpendicular to Br. For  φ = BA( BrArB=φ/A is the flux
density  [SI unit of flux is weber (Wb)]; but note that this is not correct as a defining equation as  Br is vector and  φ  and  φ/A are scalars, unit of B is tesla (T) equal to                10 -4gauss. For non-uniform B field,                       φ = ∫dφ=∫ Br. dAr. Earth's magnetic field  Bris uniform over a limited area like that of a lab; the component of this field in the horizontal directions BH is the one effectively acting on a magnet suspended or pivoted
horizontally. An artificial magnetic field is produced by a current carrying loop (see 4.2) Brc, or a bar magnet  rm in the horizontal
plane with its direction adjusted perpendicular to the magnetic meridian; this is superposed over the earth's fields  BrHwhich is always present along the magnetic meridian. The two are then perpendicular to each other; a compass needle experiences a torque exerted by these fields and comes to an
equilibrium position along the resultant field making an angle with ø with BH. Then Bc -or   Bm =BH tan ø. This is called tangent law. Deflection Magnetometer, description, settingand its working. (ii) Properties of dia, para and ferromagnetic substances; susceptibility and relative
permeability  It is better to explain the main distinction, the cause of magnetization (M) is due to magnetic dipole moment (m) of atoms, ions or molecules being for dia, >0 but very small for para and > 0 and large for ferromagnetic ; few examples; placed in external B r
, very small (induced) magnetization in a direction opposite to  B rin dia, small
magnetization parallel to  Bfor para, and large magnetization parallel to  Br for


PAPER II

PRACTICAL WORK- 20 Marks

The experiments for laboratory work and practical examinations are mostly from two groups;(i) experiments based on ray optics and ii) experiments based on current electricity.The main skill required in group (i) is to remove parallax between a needle and the real image of another needle.  In group (ii), understanding circuit diagram and making connections strictly following the given diagram is very important.  Take care of polarity of cells and meters, their range, zero error, least count, etc. A graph is a convenient and effective of representing results of measurement. Therefore, it is an important part of the experiment. Usually, there are two graphs in all question papers.  Students should learn to draw graphs correctly noting all important steps such as title, selection of origin, labelling of axes (not x and y), proper scale and the units given along each axis. Use maximum area of graph paper,  plot points with great care, mark the points plotted with   or  ⊗ and draw the best fit straight line (not necessarily passing through all  the plotted points), keeping all experimental points symmetrically placed (on the line and on the left and right side of the line) with respect to the best fit thin straight line.  Read intercepts carefully. Yintercept i.e. y0 is that value of y when x = 0. Slope ‘m’ of the best fit line should be found out using two distantpoints, one of which should be unplotted point, using 2 2 1y ymx x−=−. : 
Short answer questions may be set from each experiment to test understanding of theory and logic of steps involved. The list of experiments given below is only a general recommendation.  Teachers may add, alter or modify this list, keeping in mind the general pattern of questions asked in the annual examinations. 1. Draw the following set of graphs using data fromlens experiments - ) ν against u.  It will be a curve. ii) Magnification vum   = against  ν and to find focal length by intercept. iii) y = 100/v  against   x = 100/u  and to find f  by intercepts. 2. To find f  of a convex lens by using u-v method. 3. To find f of a convex lens by displacement method. 4. Coaxial combination of two convex lenses not in contact. 5. Using a convex lens, optical bench and two pins, obtain the positions of the  images for various positions of the object; f<u<2f, u~2f, and u>2f. 
Plot a graph of  y=100/v versus  x=100/u.  Obtain the focal length of the lens from the intercepts, read from the graph. 6. Determine the focal length of a concave lens, using an auxiliary convex lens, not in contact and plotting appropriate graph.  7. Refractive index of material of lens by Boys' method. 8. Refractive index of a liquid by using convex lens and plane mirror. 9. Using a spectrometer, measure the angle of the given prism and the angle of minimum deviation. Calculate th refractive index of the material.[A dark room is not necessary]
10. Set up a deflection magnetometer in Tan-A position, and use it to compare the dipole moments of the given bar magnets, using            (a) deflection ,method,neglecting the length of themagnets and (b) null method.11. Set up a vibration magnetometer and use it to compare the magnetic moments of the given bar magnets of equal size, but different strengths. 12. Determine the galvanometer constant of a tangent
galvanometer measuring the current (using an ammeter) and galvanometer deflection, varying the current using a rheostat.  Also, determine the
magnetic field at the centre of the galvanometer coil for different values of current and for different number of turns of the coil.  13. Using a metre bridge, determine the resistance of about 100 cm of constantan wire, measure its length and radius and hence, calculate the specificresistance of the material.
14. Verify Ohm’s law for the given unknown resistance (a 60 cm constantan wire), plotting a
graph of potential difference versus current.  Fromthe slope of the graph and the length of the wire, calculate the resistance per cm of the wire.
15. From a potentiometer set up, measure the fall in potential for increasing lengths of a constantan wire, through which a steady current is flowing; plot a graphof pd V versus length l.  Calculate the potential gradient of the wire.  Q (i) Why is the
current kept constant in this experiment?  Q (ii) How can you increase the sensitivity of the potentiometer? Q (iii) How can you use the above results and measure the emf of a cell? 16. Compare the emf of two cells using a potentiometer. 17. To study the variation in potential drop with length of slide wire for constant current, hence to determine specific resistance.