ISC Class 12th Latest Physics SYLLABUS after Cutoff

                 

         ISC PHYSICS SYLLABUS

                      Class 12th

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.

________________________________

1. 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 r1, r2 not 

necessary). Comparison with Newton’s 

law of gravitation; 

Superposition principle

(FF F F 1 12 13 14 = + + +⋅⋅⋅)     .

(b) Concept of electric field and its 

intensity; examples of different fields; 

gravitational, electric and magnetic; 

Electric field due to a point charge 

E Fq = / o

  (q0 is a test charge); E

 for 

a group of charges (superposition 

principle); a point charge q in an 

electric field E



experiences an electric 

force F qE E =   . Intensity due to a 

continuous distribution of charge i.e. 

linear, surface and volume.

(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 E

 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: 

τ = ×p E   and its derivation.

(e) Gauss’ theorem: the flux of a vector 

field; Q=vA for velocity vector v A,

 

A



is area vector. Similarly, for electric 

field E



, electric flux φE = EA for E A

 

and φE = ⋅ E A

  for uniform E



. For 

non-uniform field φE = ∫dφ =∫ E dA.

 

. 

Special cases for θ = 00

, 900 and 1800

. 

Gauss’ theorem, statement: φE =q/∈0

orφE = 0

q E dA⋅ = ∫ ∈

 

 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: Obtain expression for E



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.

-----------------------------------

2) Electrostatic Potential, Potential Energy 

andCapacitance.

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.

(a) Concept of potential, potential 

difference and potential energy.

Equipotential surface and its 

properties. Obtain an expression for 

electric potential at a point due to a 

point charge; graphical variation of E 

and V vs r, 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 = algebraic 

sum of the potentials due to each 

charge; potential due to a dipole on its 

axial line and equatorial line; also at 

any point for r>>2l (short dipole).

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 in assembling the system; U12

or U21 = (1/4πε0 ) q1q2/r12. For a 

system of 3 charges U123 = U12 + U13 + 

U23 =

0

1

4πε

1 2 13 23

12 13 23

( )

q q qq qq

rrr

+ + . 

For a dipole in a uniform electric field, 

derive an expression of the electric 

potential energy UE = - p

 . E



, special 

cases for φ =00

, 900 and 1800

(b) Capacitance of a conductor C = Q/V;

obtain the capacitance of a parallel-

plate capacitor (C = ∈0A/d) and 

equivalent capacitance for capacitors in 

series and parallel combinations. Obtain 

an expression for energy stored (U = 

1

2

CV2 =

2 1 1

2 2

Q QV 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 E

 and hence, in pd, (V);

for charge remaining the same Q = CV 

= C' V' = K. CV'; V' = V/K; 

and E E

K ′ = ; 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 0

r

A C

d

∈ ′ =       ∈

; for a capacitor 

partially filled dielectric, capacitance, 

C' =∈oA/(d-t + t/∈r).

_________________________________

2. 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. Carbon resistors, colour code 

for carbon resistors; series and parallel 

combinations of resistors; temperature 

dependence ofresistance 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 

timeτ ; 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=vdenA. Derive σ = ne2

τ/m and 

ρ = m/ne2

τ ; 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 J



= σ E



; colour coding of 

resistance. 

(b) Electrical energy consumed in time 

t is E=Pt= VIt; using Ohm’s law 

E = ( ) 2 V t R = I2

Rt. Potential difference 

V = P/ I; P = V I; Electric power consumed 

P = VI = V2 /R = I2 R; commercial units; 

electricity consumption and billing. 

Derivation of equivalent resistance for 

combination of resistors in series and 

parallel; special case of n identical 

resistors; Rs = nR and Rp = R/n.

Calculation of equivalent resistance of 

mixed grouping of resistors (circuits). 

(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=I2

R dt 

+ I2

rdt; 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 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 ∆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 

[Kirchhoff’s law not necessary]. Metre 

bridge is a modified form of Wheatstone 

bridge, its use to measure unknown 

resistance. Here R3 = l1ρ and R4=l2ρ; 

R3/R4=l1/l2. Principle of Potentiometer: fall 

in potential ∆V α ∆l; auxiliary emf ε1 is 

balanced against the fall in potential V1

across length l1. ε1 = V1 =Kl1 ; ε1/ε2 = l1/l2; 

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.

_________________________________

3. Magnetic Effect of Current and Magnetism.

--------------------------------------

(i) Moving charges and magnetis

Concept of magnetic field, Oersted's

experiment. Biot - Savart law and its 

application. Ampere's Circuital law and its 

applications to infinitely long straight wire, 

straight and toroidal solenoids (only 

qualitative treatment). 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 sensitivity. Conversion 

of galvanometer into an ammeter and a 

voltmeter.

-----------------------------------

(ii) Magnetism and Matter:

A current loop as a magnetic dipole, its 

magnetic dipole moment, magnetic dipole 

moment of a revolving electron, magnetic

field intensity due to a magnetic dipole

(bar magnet) on the axial line and 

equatorial line, torque on a magnetic dipole 

(bar magnet) in a uniform magnetic field;

bar magnet as an equivalent solenoid,

magnetic field lines; Diamagnetic, 

paramagnetic, and ferromagnetic 

substances, with examples. Electromagnets 

and factors affecting their strengths, 

permanent magnets.

(a) Only historical introduction through 

Oersted’s experiment. [Ampere’s 

swimming rule not included]. Biot-

Savart law and its vector form; 

application; derive the expression for B 

(i) at the centre of a circular loop 

carrying current; (ii) at any point on 

its axis. Current carrying loop as a 

magnetic dipole. Ampere’s Circuital 

law: statement and brief explanation. 

Apply it to obtain B

 near a long wire 

carrying current and for a solenoid 

(straight as well as torroidal). Only 

formula of B

 due to a finitely long 

conductor.

(b) Force on a moving charged particle in 

magnetic field F qv B B = × ( )    ; special 

cases, modify this equation substituting 

dl / dt for v and I for q/dt to yield F

 = 

I dl ×

 B

 for the force acting on a 

current carrying conductor placed in a 

magnetic field. Derive the expression 

for force between two long and parallel 

wires carrying current, hence, define 

ampere (the base SI unit of current)

and hence, coulomb; from Q = It. 

Lorentz force, Simple ideas about 

principle, working, and limitations of a 

cyclotron.

(c) Derive the expression for torque on a 

current carrying loop placed in a 

uniform B



, using F

 = I l B×

  and τ



= 

r F ×

  ; τ = NIAB sinφ for N turns τ



= m

 × B



, where the dipole moment

m

 = NI A

, unit: A.m2

. A current

carrying loop is a magnetic dipole; 

directions of current and B



and m



using right hand rule only; no other 

rule necessary. Mention orbital 

magnetic moment of an electron in 

Bohr model of H atom. Concept of 

radial magnetic field. Moving coil 

galvanometer; construction, principle, 

working, theory I= kφ , current and 

voltage sensitivity. Shunt. Conversion 

of galvanometer into ammeter and 

voltmeter of given range.

(d) Magnetic field represented by the 

symbol B is now defined by the 

equation F q = ov B ( × )    ; B

 is not to be 

defined in terms of force acting on a 

unit pole, etc.; note the distinction of 

B

 from E

 is that B

 forms closed 

loops as there are no magnetic 

monopoles, whereas E

 lines 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 (No 

derivations). Magnetic flux φ = B



. A



= 

BA for B uniform and B

 A



; i.e. 

area held perpendicular to For φ = 

BA( B

 A



), B=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 B

 is vector and φ and φ/A 

are scalars, unit of B is tesla (T) equal 

to 10-4 gauss. For non-uniform B

 field,

φ = ∫dφ=∫ B



. dA



(e) Properties of diamagnetic, 

paramagnetic and ferromagnetic substances; their 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 0 

for dia, >0 but very small for para and 

> 0 and large for ferromagnetic 

materials; few examples; placed in 

external B



, very small (induced) 

magnetization in a direction opposite 

to B

 in dia, small magnetization 

parallel to B

 for para, and large 

magnetization parallel to B

 for 

ferromagnetic materials; this leads to 

lines of B

 becoming less dense, more 

dense and much more dense in dia, 

para and ferro, respectively; hence, a 

weak repulsion for dia, weak attraction 

for para and strong attraction for ferro 

magnetic material. Also, a small bar 

suspended in the horizontal plane 

becomes perpendicular to the B

 field 

for dia and parallel to B

 for para and 

ferro. Defining equation H = (B/µ0)-M; 

the magnetic properties, susceptibility 

χm = (M/H) < 0 for dia (as M is 

opposite H) and >0 for para, both very 

small, but very large for ferro; hence 

relative permeability µr =(1+ χm) < 1 

for dia, > 1 for para and >>1 (very 

large) for ferro; further, χm∝1/T 

(Curie’s law) for para, independent of 

temperature (T) for dia and depends 

on T in a complicated manner for 

ferro; on heating ferro becomes para 

at Curie temperature. Electromagnet: 

its definition, properties and factors 

affecting the strength of electromagnet; 

selection of magnetic material for 

temporary and permanent magnets and 

core of the transformer on the basis of 

retentivity and coercive force (B-H 

loop and its significance, retentivity 

and coercive force not to be evaluated).

______________________________

4.Electromagnetic Induction and Alternating Currents.

--------------------------------------

(i) Electromagnetic Induction

Faraday's laws, induced emf and current;

Lenz's Law, eddy currents. Self-induction 

and mutual induction. Transformer.

--------------------------------------

(ii) Alternating Current

Peak value, mean value and RMS value of 

alternating current/voltage; their relation 

in sinusoidal case; reactance 

and impedance; LC oscillations 

(qualitative treatment only), LCR series 

circuit, resonance; power in AC circuits, 

wattless current. AC generator.

(a) Electromagnetic induction, Magnetic 

flux, change in flux, rate of change of 

flux and induced emf; Faraday’s laws. 

Lenz's law, conservation of energy; 

motional emf ε = Blv, and power P = 

(Blv)2

/R; eddy currents (qualitative); 

(b) Self-Induction, coefficient of self

           inductance, φ = LI and L dI dt = ε ; 

henry = volt. Second/ampere, 

expression for coefficient of self-

inductance of a solenoid

L

2

0 2

0

N A nA l

l

µ= = × µ . 

Mutual induction and mutual inductance (M), flux linked φ2 = MI1; 

induced emf 2

2

d

dt

φ ε = =M 1 dI

dt . 

Definition of M as 

M = 

1

2

1

2 M I or

dt

dI

ε φ= . SI unit 

henry. Expression for coefficient of 

mutual inductance of two coaxial 

solenoids. 

012

01 2

NN A M nN A

l

µ= = µ Induced 

emf opposes changes, back emf is set 

up, eddy currents. 

Transformer (ideal coupling):

principle, working and uses; step up 

and step down; efficiency and applications including transmission of 

power, energy losses and their 

minimisation.

(c) Sinusoidal variation of V and I with 

time, for the output from an 

ac generator; time period, frequency 

and phase changes; obtain mean 

values of current and voltage, obtain 

relation between RMS value of V and I 

with peak values in sinusoidal cases 

only.

(d) Variation of voltage and current in a.c. 

circuits consisting of only a resistor, 

only an inductor and only a capacitor 

(phasor representation), phase lag and 

phase lead. May apply Kirchhoff’s law 

and obtain simple differential equation 

(SHM type), V = Vo sin ωt, solution I = 

I0 sin ωt, I0sin (ωt + π/2) and I0 sin (ωt 

- π/2) for pure R, C and L circuits

respectively. Draw phase (or phasor) 

diagrams showing voltage and current 

and phase lag or lead, also showing 

resistance R, inductive reactance XL; 

(XL=ωL) and capacitive reactance XC, 

(XC= 1/ωC). Graph of XL and XC vs f.

(e) The LCR series circuit: Use phasor 

diagram method to obtain expression 

for I and V, the pd across R, L and C; 

and the net phase lag/lead; use the 

results of 4(e), V lags I by π/2 in a 

capacitor, V leads I by π/2 in an 

inductor, V and I are in phase in a 

resistor, I is the same in all three; 

hence draw phase diagram, combine 

VL and Vc (in opposite phase; 

phasors add like vectors) 

to give V=VR+VL+VC (phasor addition) 

and the max. values are related by 

V2

m=V2

Rm+(VLm-VCm)

2 when VL>VC

Substituting pd=current x 

resistance or reactance, we get 

Z2 = R2

+(XL-Xc) 2 and 

tanφ = (VL m -VCm)/VRm = (XL-Xc)/R 

giving I = I m sin (wt-φ) where I m

=Vm/Z etc. Special cases for RL and 

RC circuits. [May use Kirchoff’s law 

and obtain the differential equation]

Graph of Z vs f and I vs f.

(f) Power P associated with LCR circuit = 

1

/2VoIo cosφ =VrmsIrms cosφ = Irms2 R; 

power absorbed and power dissipated;

electrical resonance; bandwidth of 

signals and Q factor (no derivation); 

oscillations in an LC circuit (ω0 = 

1/ LC ). Average power consumed 

averaged over a full cycle P = 

(1/2) VoIo cosφ, Power factor 

cosφ = R/Z. Special case for pure R, L 

and C; choke coil (analytical only), XL

controls current but cosφ = 0, hence 

P =0, wattless current; LC circuit; at 

resonance with XL=Xc , Z=Zmin= R, 

power delivered to circuit by the 

source is maximum, resonant frequency

(g) Simple a.c. generators: Principle, 

description, theory, working and use. 

Variation in current and voltage with 

time for a.c. and d.c. Basic differences 

between a.c. and d.c.

________________________________

5. Electromagnetic Waves.

--------------------------------------

Basic idea of displacement current. 

Electromagnetic waves, their characteristics,

their transverse nature (qualitative ideas only). 

Complete electromagnetic spectrum starting 

from radio waves to gamma rays: elementary 

facts of electromagnetic waves and their uses.

Concept of displacement current, qualitative 

descriptions only of electromagnetic spectrum; 

common features of all regions of em 

spectrum including transverse nature ( E



and B



perpendicular to c



); special features of the 

common classification (gamma rays, X rays, 

UV rays, visible light, IR, microwaves, radio 

and TV waves) in their production (source), 

detection and other properties; uses; 

approximate range of λ or f or at least proper 

order of increasing f or λ.

_________________________________

6. Optics.

-------------------------------------

(i) Ray Optics and Optical Instruments.

Ray Optics: Reflection of light by

spherical mirrors, mirror formul 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.

Optical instruments: Microscopes and

astronomical telescopes (reflecting and

refracting) and their magnifying powers 

and their resolving powers.

(a) Reflection of light by spherical mirrors.

Mirror formula: its derivation; R=2f 

for spherical mirrors. Magnification.

(b) Refraction through a prism, minimum .

deviation and derivation of 

relation between n, A and δmin. Include 

explanation of i-δ graph, i1 = i2 = i 

(say) for δm; from symmetry r1 = r2; 

refracted ray inside the prism is 

parallel to the base of the equilateral 

prism. Thin prism. Dispersion; Angular 

dispersion; dispersive power, rainbow 

- ray diagram (no derivation). Simple 

explanation. Rayleigh’s theory of 

scattering of light: blue colour of sky 

and reddish appearance of the sun at 

sunrise and sunset clouds appear white.

(c) Refraction at a single spherical 

surface; detailed discussion of one case 

only - convex towards rarer medium, 

for spherical surface and real image.

Derive the relation between n1, n2, u, v 

and R. Refraction through thin lenses: 

derive lens maker's formula and lens 

formula; derivation of combined focal 

length of two thin lenses in contact. 

Combination of lenses and mirrors 

(silvering of lens excluded) and 

magnification for lens, derivation for 

biconvex lens only; extend the results 

to biconcave lens, plano convex lens 

and lens immersed in a liquid; power 

of a lens P=1/f with SI unit dioptre. 

For lenses in contact 1/F= 1/f1+1/f2

and P=P1+P2. Lens formula, formation 

of image with combination of thin 

lenses and mirrors.

[Any one sign convention may be used 

in solving numericals].

(d) Ray diagram and derivation of 

magnifying power of a simple microscope 

with image at D (least distance of distinct 

vision) and infinity; Ray diagram and 

derivation of magnifying power of a 

compound microscope with image at D.

Only expression for magnifying power of 

compound microscope for final image at infinity.

Ray diagrams of refracting telescope 

with image at infinity as well as at D; 

simple explanation; derivation of

magnifying power; Ray diagram  

of reflecting telescope with  

image at infinity. Advantages, disadvantages and 

uses. Resolving power of  

compound microscope and telescope.

-------------------------------------

(ii) Wave Optics.

Wave front and Huygen's principle. Proof

of laws of reflection and refraction

using Huygen's principle. Interference, 

Young's double slit experiment and 

expression for fringe width(β), coherent

sources and sustained interference of light,

Fraunhofer diffraction due to a single slit,

width of central maximum; polarisation,

plane polarised light, Brewster's law, uses

of plane polarised light and Polaroids.

(a) Huygen’s principle: wavefronts -

different types/shapes of wavefronts; 

proof of laws of reflection and 

refraction using Huygen’s theory. 

[Refraction through a prism and lens 

on the basis of Huygen’s theory not 

required]. 

(b) Interference of light, interference of 

monochromatic light by double slit. 

Phase of wave motion; superposition of 

identical waves at a point, path 

difference and phase difference; 

coherent and incoherent sources; 

interference: constructive and 

destructive, conditions for sustained 

interference of light waves 

[mathematical deduction of interference from the equations of two 

progressive waves with a phase 

difference is not required]. Young's 

double slit experiment: set up, 

diagram, geometrical deduction of path 

difference ∆x = dsinθ, between waves 

from the two slits; using ∆x=nλ for 

bright fringe and ∆x= (n+½)λ for dark 

fringe and sin θ = tan θ =yn /D as y 

and θ are small, obtain yn=(D/d)nλ

and fringe width β=(D/d)λ. Graph of 

distribution of intensity with angular 

distance.

(c) Single slit Fraunhofer diffraction 

(elementary explanation only).

Diffraction at a single slit:

experimental setup, diagram, 

diffraction pattern, obtain expression 

for position of minima, a sinθn= nλ, 

where n = 1,2,3… and conditions for 

secondary maxima, asinθn =(n+½)λ.; 

distribution of intensity with angular 

distance; angular width of central 

bright fringe. 

(d) Polarisation of light, plane polarised 

electromagnetic wave (elementary idea

only), methods of polarisation of light. 

Brewster's law; polaroids. Description 

of an electromagnetic wave as 

transmission of energy by periodic 

changes in E

 and B

 along the path; 

transverse nature as E

 and B

 are 

perpendicular to c



. These three 

vectors form a right handed system, so 

that E

 x B

 is along c



, they are 

mutually perpendicular to each other. 

For ordinary light, E

 and B

 are in all 

directions in a plane perpendicular to 

the c

 vector - unpolarised waves. If 

E

 and (hence B



also) is confined to a 

single plane only (⊥ c



, we have 

linearly polarized light. The plane 

containing E



 (or B



) and c



remains 

fixed. Hence, a linearly polarised light 

is also called plane polarised 

light. Plane of polarisation

(contains E c and 

  ); polarisation by 

reflection; Brewster’s law: tan ip=n; 

refracted ray is perpendicular to 

reflected ray for i= ip; ip+rp = 90° ; 

polaroids; use in the production and 

detection/analysis of polarised light, 

other uses. Law of Malus.

_________________________________

7. Dual Nature of Radiation and Matter.

------------------------------------

Wave particle duality; photoelectric effect, 

Hertz and Lenard's observations; Einstein's

photoelectric equation - particle nature of

light. Matter waves - wave nature of particles, 

de-Broglie relation; conclusion from 

Davisson-Germer experiment.

Photo electric effect, quantization of 

radiation; Einstein's equation 

Emax = hυ - W0; threshold frequency; work 

function; experimental facts of Hertz and 

Lenard and their conclusions; Einstein used 

Planck’s ideas and extended it to apply for 

radiation (light); photoelectric effect can be 

explained only assuming quantum (particle) 

nature of radiation. Determination of 

Planck’s constant (from the graph of stopping 

potential Vs versus frequency f of the 

incident light). Momentum of photon 

p=E/c=hν/c=h/λ. 

De Broglie hypothesis, phenomenon of electron 

diffraction (qualitative only). Wave nature of 

radiation is exhibited in interference, 

diffraction and polarisation; particle nature is 

exhibited in photoelectric effect. Dual nature 

of matter: particle nature common in that it 

possesses momentum p and kinetic energy KE. 

The wave nature of matter was proposed by 

Louis de Broglie, λ=h/p= h/mv. Davisson and 

Germer experiment; qualitative description of 

the experiment and conclusion.

_________________________________

8.Atoms and  Nuclel.

--------------------------------------

(i) Atoms

Alpha-particle scattering experiment;

Rutherford's atomic model; Bohr’s atomic 

model, energy levels, hydrogen spectrum.

Rutherford’s nuclear model of atom 

(mathematical theory of scattering 

excluded), based on Geiger - Marsden 

experiment on α-scattering; 

nuclear radius r in terms of closest approach of α particle to the nucleus, 

obtained by equating ∆K=½ mv2

 of the α

particle to the change in electrostatic 

potential energy ∆U of the system 

[ 0 0 4

2e Ze U πε r

× = r0∼10-15m = 1 fermi; atomic

structure; only general qualitative ideas, 

including atomic number Z, Neutron 

number N and mass number A. A brief 

account of historical background leading 

to Bohr’s theory of hydrogen spectrum; 

formulae for wavelength in Lyman, Balmer, 

Paschen, Brackett and Pfund series.

Rydberg constant. Bohr’s model of H 

atom, postulates (Z=1); expressions for 

orbital velocity, kinetic energy, potential 

energy, radius of orbit and total energy of 

electron. Energy level diagram, calculation 

of ∆E, frequency and wavelength of 

different lines of emission spectra; 

agreement with experimentally observed 

values. [Use nm and not Å for unit ofλ].

------------------------------------- 

(ii) Nuclei.

Composition and size of nucleus, 

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 reactions, nuclear fission

and nuclearfusion.

(a) Atomic masses and nuclear density; 

Isotopes, Isobars and Isotones 

definitions with examples of each. 

Unified atomic mass unit, symbol u, 

1u=1/12 of the mass of 12C atom = 

1.66x10-27kg). Composition of nucleus; 

mass defect and binding energy, BE= 

(∆m) c2

. Graph of BE/nucleon versus 

mass number A, special features - less 

BE/nucleon for light as well as heavy 

elements. Middle order more stable 

[see fission and fusion] Einstein’s 

equation E=mc2

. Calculations related 

to this equation; mass defect/binding 

energy, mutual annihilation and 

pair production as examples.

(b) Radioactivity: discovery; spontaneous 

disintegration of an atomic nucleus 

with the emission of α or β particles 

and γ radiation, unaffected by 

physical and chemical changes. 

Radioactive decay law; derivation of 

N = Noe-λt

; half-life period T; graph 

of N versus t, with T marked on 

the X axis. Relation between 

half-life (T) and disintegration 

constant ( λ); mean life ( τ) and its 

relation with λ. Value of T of some 

common radioactive elements. 

Examples of a few nuclear reactions 

with conservation of mass number and 

charge, concept of a neutrino. 

Changes taking place within the 

nucleus included. [Mathematical 

theory of α and β decay not included]. 

(c) Nuclear Energy

Theoretical (qualitative) prediction of 

exothermic (with release of energy) 

nuclear reaction, in fusing together two 

light nuclei to form a heavier nucleus 

and in splitting heavy nucleus to form 

middle order (lower mass number) 

nuclei, is evident from the shape of BE 

per nucleon versus mass number 

graph. Also calculate the 

disintegration energy Q for a heavy 

nucleus (A=240) with BE/A ∼ 7.6 MeV 

per nucleon split into two equal halves 

with A=120 each and BE/A ∼ 8.5 

MeV/nucleon; Q ∼ 200 MeV. Nuclear

fission: Any one equation of fission 

reaction. Chain reaction- controlled 

and uncontrolled; nuclear reactor and 

nuclear bomb. Main parts of a nuclear 

reactor including their functions - fuel 

elements, moderator, control rods, 

coolant, casing; criticality; utilization 

of energy output - all qualitative only. 

Fusion, simple example of 4 1

H→4

He 

and its nuclear reaction equation; 

requires very high temperature ∼ 106

degrees; difficult to achieve; hydrogen 

bomb; thermonuclear energy 

production in the sun and stars. 

[Details of chain reaction not required].

_________________________________

9.Electronic Devices.

-----------------------------------

(i) Semiconductor Electronics: Materials, 

Devices and SimpleCircuits. Energy bands

in conductors, semiconductors and

insulators (qualitative ideas only). Intrinsic 

and extrinsic semiconductors.

(ii) Semiconductor diode: I-V characteristics in 

forward and reverse bias, diode as a 

rectifier; Special types of junction diodes: 

LED, photodiode, solar cell and Zener 

diode and its characteristics, zener diode as 

a voltage regulator.

(a) Energy bands in solids; energy band 

diagrams for distinction between 

conductors, insulators and semi-

conductors - intrinsic and extrinsic; 

electrons and holes in semiconductors.

Elementary ideas about electrical 

conduction in metals [crystal structure 

not included]. Energy levels (as for 

hydrogen atom), 1s, 2s, 2p, 3s, etc. of 

an isolated atom such as that of 

copper; these split, eventually forming 

‘bands’ of energy levels, as we 

consider solid copper made up of a 

large number of isolated atoms, 

brought together to form a lattice; 

definition of energy bands - groups of 

closely spaced energy levels separated 

by band gaps called forbidden bands. 

An idealized representation of the 

energy bands for a conductor, 

insulator and semiconductor; 

characteristics, differences; distinction 

between conductors, insulators and 

semiconductors on the basis of energy 

bands, with examples; qualitative 

discussion only; energy gaps (eV) in 

typical substances (carbon, Ge, Si); 

some electrical properties of 

semiconductors. Majority and minority 

charge carriers - electrons and holes; 

intrinsic and extrinsic, doping, p-type, 

n-type; donor and acceptor impurities.

(b) Junction diode and its symbol; 

depletion region and potential barrier; 

forward and reverse biasing, V-I 

characteristics and numericals; half 

wave and a full wave rectifier. Simple 

circuit diagrams and graphs, function 

of each component in the electric 

circuits, qualitative only. [Bridge 

rectifier of 4 diodes not included];

elementary ideas on solar cell, 

photodiode and light emitting diode 

(LED) as semi conducting diodes. 

Importance of LED’s as they save 

energy without causing atmospheric 

pollution and global warming. Zener 

diode, V-I characteristics, circuit 

diagram and working of zener diode as

a voltage regulator.

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