PHYSICS (861)

CLASS XII

There will be two papers in the subject:

Paper II: Practical - 3 hours ... 15 marks
Paper I: Theory - 3 hours ...70 marks
Project Work ... 10 marks
Practical File ... 5 marks

PAPER I- THEORY: 70 Marks

S. NO. UNIT TOTAL WEIGHTAGE

1. Electrostatics 14 Marks

2. Current Electricity

3. Magnetic Effects of Current and Magnetism

16 Marks
4. Electromagnetic Induction and Alternating Currents

5. Electromagnetic Waves

6. Optics 20 Marks

7. Dual Nature of Radiation and Matter 13 Marks

8. Atoms and Nuclei

9. Electronic Devices 7 Marks

TOTAL 70 Marks

1
 
PAPER I -THEORY- 70 Marks field E experiences an electric
 
Note: (i) Unless otherwise specified, only S. I. Units force FE = qE . Intensity due to a
are to be used while teaching and learning, as well as
continuous distribution of charge i.e.
for answering questions.
linear, surface and volume.
(ii) All physical quantities to be defined as and when
(c) Electric lines of force: A convenient way
they are introduced along with their units and
to visualize the electric field; properties
dimensions.
of lines of force; examples of the lines of
(iii) Numerical problems are included from all topics force due to (i) an isolated point charge
except where they are specifically excluded or where (+ve and - ve); (ii) dipole, (iii) two
only qualitative treatment is required. similar charges at a small distance;(iv)
uniform field between two oppositely
1. Electrostatics charged parallel plates.
(i) Electric Charges and Fields (d) Electric dipole and dipole moment;

Electric charges; conservation and derivation of the E at a point, (1) on the
quantisation of charge, Coulomb's law; axis (end on position) (2) on the
superposition principle and continuous perpendicular bisector (equatorial i.e.
charge distribution. broad side on position) of a dipole, also
Electric field, electric field due to a point for r>> 2l (short dipole); dipole in a
charge, electric field lines, electric dipole, uniform electric field; net force zero,
electric field due to a dipole, torque on a torque on an electric dipole:
dipole in uniform electric field.   
τ= p × E and its derivation.
Electric flux, Gauss’s theorem in (e) Gauss’ theorem: the flux of a vector
Electrostatics and its applications to find  
field due to infinitely long straight wire, field; Q=vA for velocity vector v A,
uniformly charged infinite plane sheet and 
A is area vector. Similarly, for electric
uniformly charged thin spherical shell.   
field E , electric flux φE = EA for E A
(a) Coulomb's law, S.I. unit of   
charge; permittivity of free space and φE= E ⋅ A for uniform E . For non-
and of dielectric medium.  
Frictional electricity, electric charges uniform field φE = ∫dφ =∫ E.dA . Special
(two types); repulsion and cases for θ = 00, 900 and 1800. Gauss’
attraction; simple atomic structure - theorem, statement: φE =q/∈0
electrons and ions; conductors or φE = where φE is for
and insulators; quantization and
conservation of electric charge; a closed surface; q is the net charge
Coulomb's law in vector form; (position enclosed, ∈o is the permittivity of free
coordinates r1, r2 not necessary). space. Essential properties of a Gaussian
Comparison with Newton’s law of surface.
gravitation; Superposition principle 
    Applications: Obtain expression for E
( F
= 1 )
F 12 + F 13 + F 14 + ⋅⋅⋅ . due to 1. an infinite line of charge, 2. a
(b) Concept of electric field and its intensity; uniformly charged infinite plane thin
examples of different fields; sheet, 3. a thin hollow spherical shell
gravitational, electric and magnetic; (inside, on the surface and outside).
Electric field due to a point charge Graphical variation of E vs r for a thin
   spherical shell.
E = F / qo (q0 is a test charge); E for a
(ii) Electrostatic Potential, Potential Energy and
group of charges (superposition Capacitance
principle); a point charge q in an electric

2
 Electric potential, potential difference, 1 2
electric potential due to a point charge, a expression for energy stored (U = CV
2
dipole and system of charges; equipotential
surfaces, electrical potential energy of a 1 1 Q2
= QV = ) and energy density.
system of two point charges and of electric 2 2 C
dipole in an electrostatic field.
(c) Dielectric constant K = C'/C; this is also
Conductors and insulators, free charges and called relative permittivity K = ∈r = ∈/∈o;
bound charges inside a conductor. elementary ideas of polarization of matter
Dielectrics and electric polarisation, in a uniform electric field qualitative
capacitors and capacitance, combination discussion; induced surface charges
of capacitors in series and in parallel. weaken the original field; results in
Capacitance of a parallel plate capacitor,

reduction in E and hence, in pd, (V); for
energy stored in a capacitor. charge remaining the same Q = CV = C'
(a) Concept of potential, potential difference V' = K. CV'; V' = V/K; and E ′ = E ; if
and potential energy. Equipotential K
surface and its properties. Obtain an the Capacitor is kept connected with the
expression for electric potential at a source of emf, V is kept constant V = Q/C =
point due to a point charge; graphical Q'/C' ; Q'=C'V = K.
variation of E and V vs r, VP=W/q0; CV= K. Q increases; For a parallel plate
hence VA -VB = WBA/ q0 (taking q0 from B capacitor with a dielectric in between,
to A) = (q/4πε0)(1/rA - 1/rB); derive this C' = KC = K.∈o . A/d = ∈r .∈o .A/d.
equation; also VA = q/4πε0 .1/rA ; for ∈0 A
Then C ′ = ; for a capacitor
q>0, VA>0 and for q<0, VA < 0. For a d 
collection of charges V = algebraic sum  ∈ 
 r 
of the potentials due to each charge; partially filled dielectric, capacitance,
potential due to a dipole on its axial line C' =∈oA/(d-t + t/∈r).
and equatorial line; also at any point for
r>>2l (short dipole). Potential energy of 2. Current Electricity

a point charge (q) in an electric field E ,
Mechanism of flow of current in conductors.
placed at a point P where potential is V,
Mobility, drift velocity and its relation with
is given by U =qV and ∆U =q (VA-VB) .
electric current; Ohm's law and its proof,
The electrostatic potential energy of a
resistance and resistivity and their relation to
system of two charges = work done
drift velocity of electrons; V-I characteristics
W21=W12 in assembling the system; U12
(linear and non-linear), electrical energy and
or U21 = (1/4πε0 ) q1q2/r12. For a system power, electrical resistivity and conductivity.
of 3 charges U123 = U12 + U13 + U23 Temperature dependence of resistance and
1 q1 q 2 q1 q3 q 2 q3 resistivity.
= ( + ) . For a
+
4πε 0 r12 r13 r23 Internal resistance of a cell, potential
dipole in a uniform electric field, derive difference and emf of a cell, combination of
an expression of the electric potential cells in series and in parallel, Kirchhoff's laws
  and simple applications, Wheatstone bridge,
energy UE = - p . E , special cases for φ
=00, 900 and 1800. metre bridge. Potentiometer - principle and its
applications to measure potential difference, to
(b) Capacitance of a conductor C = Q/V; compare emf of two cells; to measure internal
obtain the capacitance of a parallel-plate resistance of a cell.
capacitor (C = ∈0A/d) and equivalent
(a) Free electron theory of conduction;
capacitance for capacitors in series and
acceleration of free electrons, relaxation
parallel combinations. Obtain an
time τ ; electric current I = Q/t; concept of

3
 drift velocity and electron mobility. Ohm's ∆V=+ε and going from +ve to -ve terminal
law, current density J = I/A; experimental through the cell, we are going down, so ∆V =
verification, graphs and slope, ohmic -ε. Application to simple circuits. Wheatstone
and non-ohmic conductors; obtain the bridge; right in the beginning take Ig=0 as we
relation I=vdenA. Derive σ = ne2τ/m and consider a balanced bridge, derivation of
ρ = m/ne2 τ ; effect of temperature on R1/R2 = R3/R4 [Kirchhoff’s law not
resistivity and resistance of conductors and necessary]. Metre bridge is a modified form
semiconductors and graphs. Resistance R= of Wheatstone bridge, its use to measure
V/I; resistivity ρ, given by R = ρ.l/A; unknown resistance. Here R3 = l1ρ and
conductivity and conductance; Ohm’s law as R4=l2ρ; R3/R4=l1/l2. Principle of
 
J=σ E. Potentiometer: fall in potential ∆V α ∆l;
auxiliary emf ε1 is balanced against the fall
(b) Electrical energy consumed in time
in potential V1 across length l1. ε1 = V1 =Kl1 ;
t is E=Pt= VIt; using Ohm’s law
ε1/ε2 = l1/l2; potentiometer as a voltmeter.
E = (V R ) t
2
= I2Rt. Potential difference Potential gradient and sensitivity of
potentiometer. Use of potentiometer: to
V = P/ I; P = V I; Electric power consumed compare emfs of two cells, to determine
P = VI = V2 /R = I2 R; commercial units; internal resistance of a cell.
electricity consumption and billing.
3. Magnetic Effects of Current and Magnetism
(c) The source of energy of a seat of emf (such
as a cell) may be electrical, mechanical, (i) Moving charges and magnetism
thermal or radiant energy. The emf of a Concept of magnetic field, Oersted's
source is defined as the work done per unit experiment. Biot - Savart law and its
charge to force them to go to the higher point application. Ampere's Circuital law and its
of potential (from -ve terminal to +ve applications to infinitely long straight wire,
terminal inside the cell) so, ε = dW /dq; but straight solenoid (only qualitative treatment).
dq = Idt; dW = εdq = εIdt . Equating total Force on a moving charge in uniform
work done to the work done across the magnetic and electric fields. Force on a
external resistor R plus the work done across current-carrying conductor in a uniform
the internal resistance r; εIdt=I2R dt + I2rdt; magnetic field, force between two parallel
ε =I (R + r); I=ε/( R + r ); also IR +Ir = ε current-carrying conductors-definition of
or V=ε- Ir where Ir is called the back emf as ampere, torque experienced by a current loop
it acts against the emf ε; V is the terminal pd. in uniform magnetic field; moving coil
Derivation of formulae for combination for galvanometer - its sensitivity. Conversion of
identical cells in series, parallel and mixed galvanometer into an ammeter and a
grouping. Parallel combination of two cells voltmeter.
of unequal emf. Series combination of n cells (ii) Magnetism and Matter
of unequal emf.
A current loop as a magnetic dipole, its
(d) Statement and explanation of Kirchhoff's magnetic dipole moment, magnetic dipole
laws with simple examples. The first is a moment of a revolving electron, magnetic
conservation law for charge and the 2nd is field intensity due to a magnetic dipole (bar
law of conservation of energy. Note change magnet) on the axial line and equatorial line,
in potential across a resistor ∆V=IR<0 when torque on a magnetic dipole (bar magnet) in a
we go ‘down’ with the current (compare with uniform magnetic field; bar magnet as an
flow of water down a river), and ∆V=IR>0 if equivalent solenoid, magnetic field lines.
we go up against the current across the Electromagnets and factors affecting their
resistor. When we go through a cell, the -ve strengths, permanent magnets.
terminal is at a lower level and the +ve
terminal at a higher level, so going from -ve (a) Only historical introduction through
to +ve through the cell, we are going up and Oersted’s experiment. [Ampere’s

4
 
swimming rule not included]. Biot-Savart magnetic monopoles, whereas E lines
law and its vector form; application; start from +ve charge and end on -ve
derive the expression for B (i) at the charge. Magnetic field lines due to a
centre of a circular loop carrying magnetic dipole (bar magnet). Magnetic
current; (ii) at any point on its axis. field in end-on and broadside-on
Current carrying loop as a magnetic positions (No derivations). Magnetic flux
dipole. Ampere’s Circuital law:  
φ = B . A = BA for B uniform and
statement and brief explanation. Apply it  
 B A ; i.e. area held perpendicular to
to obtain B near a long wire carrying
current and for a solenoid. Only formula  
 For φ = BA( B A ), B=φ/A is the flux
of B due to a finitely long conductor. density [SI unit of flux is weber (Wb)];
(b) Force on a moving charged particle in but note that this is not correct as a
  
( )
FB q v × B ; special
magnetic field = defining equation as B is vector and φ
and φ/A are scalars, unit of B is tesla (T)
cases, modify this equation substituting 
 equal to 10-4 gauss. For non-uniform B
dl / dt for v and I for q/dt to yield F =  
  field, φ = ∫dφ=∫ B . dA .
I dl × B for the force acting on a current
carrying conductor placed in a magnetic 4. Electromagnetic Induction and Alternating
field. Derive the expression for force Currents
between two long and parallel wires (i) Electromagnetic Induction
carrying current, hence, define ampere
(the base SI unit of current) and hence, Faraday's laws, induced emf and current;
coulomb; from Q = It. Lorentz force. Lenz's Law, eddy currents. Self-induction
and mutual induction. Transformer.
(c) Derive the expression for torque on a
current carrying loop placed in a (ii) Alternating Current
    
uniform B , using F = I l × B and τ = Peak value, mean value and RMS value of
   alternating current/voltage; their relation in
r × F ; τ = NIAB sin φ for N turns τ
   sinusoidal case; reactance and impedance;
= m × B , where the dipole moment m = LC oscillations (qualitative treatment only),

NI A , unit: A.m2. A current carrying LCR series circuit, resonance; power in AC
loop is a magnetic dipole; directions of circuits, wattless current. AC generator.
 
current and B and m using right hand (a) Electromagnetic induction, Magnetic
rule only; no other rule necessary. flux, change in flux, rate of change of
Mention orbital magnetic moment of an flux and induced emf; Faraday’s laws.
electron in Bohr model of H atom. Lenz's law, conservation of energy;
Concept of radial magnetic field. Moving motional emf ε = Blv, and power P =
coil galvanometer; construction, (Blv)2/R; eddy currents (qualitative);
principle, working, theory I= k φ ,
(b) Self-Induction, coefficient of self-
current and voltage sensitivity. Shunt.
Conversion of galvanometer into inductance, φ = LI and L = ε ;
dI dt
ammeter and voltmeter of given range. henry = volt. Second/ampere, expression
(d) Magnetic field represented by the symbol for coefficient of self-inductance of a
B is now defined by the equation µ0 N 2 A
  =
solenoid L = µ0 n 2 A × l .
F = qo ( v × B ) ; B is not to be defined in
 
l
terms of force acting on a unit pole, etc.; Mutual induction and mutual inductance
 
note the distinction of B from E is that (M), flux linked φ2 = MI1; induced emf

B forms closed loops as there are no
5
 dφ2 dI combine VL and Vc (in opposite phase;
ε2 = =M 1 . Definition of M as phasors add like vectors) to
dt dt
give V=VR+VL+VC (phasor addition) and
ε2 or M = φ 2 the max. values are related by
M = . SI unit
dI 1 I1 V2m=V2Rm+(VLm-VCm)2 when VL>VC
dt Substituting pd=current x
henry. Expression for coefficient of resistance or reactance, we get
mutual inductance of two coaxial Z2=R2+(XL-Xc)2 and
solenoids. tanφ = (VL m -VCm)/VRm = (XL-Xc)/R
µ0 N1 N 2 A giving I = I m sin (wt-φ) where I m =Vm/Z
=M = µ0 n1 N 2 A Induced etc. Special cases for RL and RC circuits.
l
[May use Kirchoff’s law and obtain the
emf opposes changes, back emf is set up,
differential equation] Graph of Z vs f and
eddy currents.
I vs f.
Transformer (ideal coupling): principle,
(f) Power P associated with LCR circuit =
working and uses; step up and step
down; efficiency and applications
1
/2VoIo cosφ =VrmsIrms cosφ = Irms2 R;
including transmission of power, energy power absorbed and power dissipated;
losses and their minimisation. electrical resonance; bandwidth of
signals and Q factor (no derivation);
(c) Sinusoidal variation of V and I with time, oscillations in an LC circuit (ω0 =
for the output from an ac
1/ LC ). Average power consumed
generator; time period, frequency and
phase changes; obtain mean values of averaged over a full cycle P=
current and voltage, obtain relation (1/2) VoIo cosφ, Power factor
between RMS value of V and I with peak cosφ = R/Z. Special case for pure R, L
values in sinusoidal cases only. and C; choke coil (analytical only), XL
controls current but cosφ = 0, hence
(d) Variation of voltage and current in a.c.
circuits consisting of only a resistor, only P =0, wattless current; LC circuit; at
an inductor and only a capacitor (phasor resonance with XL=Xc , Z=Zmin= R, power
representation), phase lag and phase delivered to circuit by the source is
lead. May apply Kirchhoff’s law and maximum, resonant frequency
obtain simple differential equation (SHM 1
f0 = .
type), V = Vo sin ωt, solution I = I0 sin 2π LC
ωt, I0sin (ωt + π/2) and I0 sin (ωt - π/2)
for pure R, C and L circuits respectively. (g) Simple a.c. generators: Principle,
Draw phase (or phasor) diagrams description, theory, working and use.
showing voltage and current and phase Variation in current and voltage with
lag or lead, also showing resistance R, time for a.c. and d.c. Basic differences
inductive reactance XL; (XL=ωL) and between a.c. and d.c.
capacitive reactance XC, (XC = 1/ωC).
5. Electromagnetic Waves
Graph of XL and XC vs f.
Basic idea of displacement current.
(e) The LCR series circuit: Use phasor
Electromagnetic waves, their characteristics, their
diagram method to obtain expression for
transverse nature (qualitative ideas only).
I and V, the pd across R, L and C; and
Complete electromagnetic spectrum starting from
the net phase lag/lead; use the results of
radio waves to gamma rays: elementary facts of
4(e), V lags I by π/2 in a capacitor, V electromagnetic waves and their uses.
leads I by π/2 in an inductor, V and I are
in phase in a resistor, I is the same in all Concept of displacement current, qualitative
three; hence draw phase diagram, descriptions only of electromagnetic spectrum;
common features of all regions of

6
 electromagnetic spectrum including transverse (d) Refraction at a single spherical surface;
nature ( and perpendicular to ); special detailed discussion of one case only -
features of the common classification (gamma convex towards rarer medium, for
rays, X rays, UV rays, visible light, IR, spherical surface and real image. Derive
microwaves, radio and TV waves) in their the relation between n1, n2, u, v and R.
production (source), detection and other Refraction through thin lenses: derive
properties; uses; approximate range of λ or f or lens maker's formula and lens formula;
at least proper order of increasing f or λ. derivation of combined focal length of
two thin lenses in contact. Combination
6. Optics of lenses and mirrors (silvering of lens
excluded) and magnification for lens,
(i) Ray Optics and Optical Instruments derivation for biconvex lens only; extend
Ray Optics: Reflection of light by the results to biconcave lens, plano
spherical mirrors, mirror formula, convex lens and lens immersed in a
refraction of light at plane surfaces, total liquid; power of a lens P=1/f with SI
internal reflection and its applications, unit dioptre. For lenses in contact 1/F=
optical fibres, refraction at spherical 1/f1+1/f2 and P=P1+P2. Lens formula,
surfaces, lenses, thin lens formula, lens formation of image with combination of
maker's formula, magnification, power of thin lenses and mirrors.
a lens, combination of thin lenses in [Any one sign convention may be used in
contact, combination of a lens and a mirror, solving numericals].
refraction and dispersion of light through a (e) Ray diagram and derivation of
prism. magnifying power of a simple
Optical instruments: Microscopes and microscope with image at D (least
astronomical telescopes (reflecting and distance of distinct vision) and infinity;
refracting) and their magnifying powers. Ray diagram and derivation of
magnifying power of a compound
(a) Reflection of light by spherical mirrors.
microscope with image at D. Only
Mirror formula: its derivation; R=2f for expression for magnifying power of
spherical mirrors. Magnification. compound microscope for final image at
(b) Refraction of light at a plane interface, infinity.
Snell's law; total internal reflection and Ray diagrams of refracting telescope
critical angle; total reflecting prisms and with image at infinity as well as at D;
optical fibers. Total reflecting prisms: simple explanation; derivation of
application to triangular prisms with magnifying power; Ray diagram of
angle of the prism 300, 450, 600 and 900 reflecting telescope with image at
respectively; ray diagrams for Refraction infinity. Advantages, disadvantages and
through a combination of uses.
1 , real depth
media, 1 n2 × 2 n3 × 3 n1 =
(ii) Wave Optics
and apparent depth. Simple applications.
Wave front and Huygen's principle. Proof
(c) Refraction through a prism, minimum of laws of reflection and refraction using
deviation and derivation of Huygen's principle. Interference, Young's
relation between n, A and δmin. Include double slit experiment and expression for
explanation of i-δ graph, i1 = i2 = i (say) fringe width(β), coherent sources and
for δm; from symmetry r1 = r2; refracted sustained interference of light, Fraunhofer
ray inside the prism is parallel to the diffraction due to a single slit, width of
base of the equilateral prism. Thin prism. central maximum.
Dispersion; Angular dispersion; (a) Huygen’s principle: wavefronts - different
dispersive power, rainbow - ray diagram types/shapes of wavefronts; proof of laws
(no derivation). Simple explanation.

7
 of reflection and refraction using explained only assuming quantum (particle)
Huygen’s theory. [Refraction through a nature of radiation. Determination of
prism and lens on the basis of Huygen’s Planck’s constant (from the graph of
theory not required]. stopping potential Vs versus frequency f of
(b) Interference of light, interference of the incident light). Momentum of photon
monochromatic light by double slit. p=E/c=hν/c=h/λ.
Phase of wave motion; superposition of (b) De Broglie hypothesis, phenomenon
identical waves at a point, path of electron diffraction (qualitative only).
difference and phase difference; coherent Wave nature of radiation is exhibited in
and incoherent sources; interference: interference, diffraction and polarisation;
constructive and destructive, conditions particle nature is exhibited in photoelectric
for sustained interference of light waves effect. Dual nature of matter: particle nature
[mathematical deduction of interference common in that it possesses momentum p and
from the equations of two progressive kinetic energy KE. The wave nature of
waves with a phase difference is not matter was proposed by Louis de Broglie,
required]. Young's double slit λ=h/p= h/mv.
experiment: set up, diagram, geometrical
deduction of path difference ∆x = dsinθ, 8. Atoms and Nuclei
between waves from the two slits; using (i) Atoms
∆x=nλ for bright fringe and ∆x= (n+½)λ
Alpha-particle scattering experiment;
for dark fringe and sin θ = tan θ =yn /D
Rutherford's atomic model; Bohr’s atomic
as y and θ are small, obtain yn=(D/d)nλ
model, energy levels, hydrogen spectrum.
and fringe width β=(D/d)λ. Graph of
distribution of intensity with angular Rutherford’s nuclear model of atom
distance. (mathematical theory of scattering excluded),
based on Geiger - Marsden experiment on
(c) Single slit Fraunhofer diffraction
α-scattering; nuclear radius r in terms of
(elementary explanation only).
closest approach of α particle to the nucleus,
Diffraction at a single slit: experimental
setup, diagram, diffraction pattern, obtained by equating ∆K=½ mv2 of the α
obtain expression for position of minima, particle to the change in electrostatic
a sinθn= nλ, where n = 1,2,3… and potential energy ∆U of the system
conditions for secondary maxima, asinθn [ U = 2e × Ze r0∼10-15m = 1 fermi; atomic
4πε 0 r0
=(n+½)λ.; distribution of intensity with
structure; only general qualitative ideas,
angular distance; angular width of
including atomic number Z, Neutron number
central bright fringe.
N and mass number A. A brief account of
7. Dual Nature of Radiation and Matter historical background leading to Bohr’s
Wave particle duality; photoelectric effect, theory of hydrogen spectrum; formulae for
Hertz and Lenard's observations; Einstein's wavelength in Lyman, Balmer, Paschen,
photoelectric equation - particle nature of light. Brackett and Pfund series. Rydberg constant.
Matter waves - wave nature of particles, Bohr’s model of H atom, postulates (Z=1);
de-Broglie relation. expressions for orbital velocity, kinetic
energy, potential energy, radius of orbit and
(a) Photo electric effect, quantization of total energy of electron. Energy level
radiation; Einstein's equation diagram, calculation of ∆E, frequency and
Emax = hυ - W0; threshold frequency; work wavelength of different lines of emission
function; experimental facts of Hertz and spectra; agreement with experimentally
Lenard and their conclusions; Einstein used observed values. [Use nm and not Å for unit
Planck’s ideas and extended it to apply for ofλ].
radiation (light); photoelectric effect can be

8
(ii) Nuclei production in the sun and stars. [Details
of chain reaction not required].
Composition and size of nucleus. Mass-
energy relation, mass defect; binding 9. Electronic Devices
energy per nucleon and its variation with (i) Semiconductor Electronics: Materials,
mass number; Nuclear reactions, nuclear Devices and Simple Circuits. Energy bands in
fission and nuclear fusion. conductors, semiconductors and insulators
(a) Atomic masses and nuclear density; (qualitative ideas only). Intrinsic and
Isotopes, Isobars and Isotones – extrinsic semiconductors.
definitions with examples of each. (ii) Semiconductor diode: I-V characteristics in
Unified atomic mass unit, symbol u, forward and reverse bias, diode as a rectifier;
1u=1/12 of the mass of 12C atom = Special types of junction diodes: LED,
1.66x10-27kg). Composition of nucleus; photodiode and solar cell.
mass defect and binding energy, BE=
(a) Energy bands in solids; energy band
(∆m) c2. Graph of BE/nucleon versus diagrams for distinction between
mass number A, special features - less conductors, insulators and semi-
BE/nucleon for light as well as heavy conductors - intrinsic and extrinsic;
elements. Middle order more stable [see electrons and holes in semiconductors.
fission and fusion] Einstein’s equation
E=mc2. Calculations related to this Elementary ideas about electrical
equation; mass defect/binding energy, conduction in metals [crystal structure
mutual annihilation and pair production not included]. Energy levels (as for
as examples. hydrogen atom), 1s, 2s, 2p, 3s, etc. of an
isolated atom such as that of copper;
(b) Nuclear Energy these split, eventually forming ‘bands’ of
Theoretical (qualitative) prediction of energy levels, as we consider solid
exothermic (with release of energy) copper made up of a large number of
nuclear reaction, in fusing together two isolated atoms, brought together to form
light nuclei to form a heavier nucleus a lattice; definition of energy bands -
and in splitting heavy nucleus to form groups of closely spaced energy levels
middle order (lower mass number) separated by band gaps called forbidden
nuclei, is evident from the shape of BE bands. An idealized representation of the
per nucleon versus mass number graph. energy bands for a conductor,
Also calculate the disintegration energy insulator and semiconductor;
Q for a heavy nucleus (A=240) with characteristics, differences; distinction
BE/A ∼ 7.6 MeV per nucleon split into between conductors, insulators and
two equal halves with A=120 each and semiconductors on the basis of energy
BE/A ∼ 8.5 MeV/nucleon; Q ∼ 200 MeV. bands, with examples; qualitative
Nuclear fission: Any one equation of discussion only; energy gaps (eV) in
fission reaction. Chain reaction- typical substances (carbon, Ge, Si); some
controlled and uncontrolled; nuclear electrical properties of semiconductors.
reactor and nuclear bomb. Main parts of Majority and minority charge carriers -
a nuclear reactor including their electrons and holes; intrinsic and
functions - fuel elements, moderator, extrinsic, doping, p-type, n-type; donor
control rods, coolant, casing; criticality; and acceptor impurities.
utilization of energy output - all (b) Junction diode and its symbol; depletion
qualitative only. Fusion, simple example region and potential barrier; forward
of 4 1H→4He and its nuclear reaction and reverse biasing, V-I characteristics
equation; requires very high temperature and numericals; half wave and a full
∼ 106 degrees; difficult to achieve; wave rectifier. Simple circuit diagrams
hydrogen bomb; thermonuclear energy and graphs, function of each component

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 in the electric circuits, qualitative only. (ii) Selection of origin (should be marked by two
[Bridge rectifier of 4 diodes not coordinates, example 0,0 or 5,0, or 0,10 or 30,5;
included]; elementary ideas on solar Kink is not accepted).
cell, photodiode and light emitting diode (i) The axes should be labelled according to the
(LED) as semi conducting diodes. question
Importance of LED’s as they save energy
without causing atmospheric pollution (ii) Uniform and convenient scale should be taken
and global warming. and the units given along each axis (one small
division = 0.33, 0.67, 0.66, etc. should not to be
PAPER II taken)
PRACTICAL WORK- 15 Marks (iii) Maximum area of graph paper (at least 60% of
The experiments for laboratory work and practical the graph paper along both the axes) should
examinations are mostly from two groups: be used.
(i) experiments based on ray optics and
(iv) Points should be plotted with great care,
(ii) experiments based on current electricity.
marking the points plotted with (should be a
The main skill required in group (i) is to remove circle with a dot)  or ⊗ . A blob ( ) is a
parallax between a needle and the real image of
misplot.
another needle.
(v) The best fit straight line should be drawn. The
In group (ii), understanding circuit diagram and
making connections strictly following the given best fit line does not necessarily have to pass
diagram is very important. Polarity of cells and through all the plotted points and the origin.
meters, their range, zero error, least count, etc. should While drawing the best fit line, all
be taken care of. experimental points must be kept on the line
or symmetrically placed on the left and right
A graph is a convenient and effective way of
side of the line. The line should be continuous,
representing results of measurement. It is an
important part of the experiment. thin, uniform and extended beyond the extreme
plots.
There will be one graph in the Practical question
paper. (vi) The intercepts must be read carefully.
Y intercept i.e. y0 is that value of y when x = 0.
Candidates are advised to read the question paper Similarly, X intercept i.e. x0 is that value of x
carefully and do the work according to the
when y=0. When x0 and y0 are to be read,
instructions given in the question paper. Generally
they are not expected to write the procedure of the origin should be at (0, 0).
experiment, formulae, precautions, or draw the Deductions
figures, circuit diagrams, etc.
(i) The slope ‘S’ of the best fit line must be found
Observations should be recorded in a tabular form. taking two distant points (using more than 50%
Record of observations of the line drawn), which are not the plotted
y − y1 ∆y
• All observations recorded should be consistent points, using S = 2 = . Slope S must
with the least count of the instrument used (e.g. x2 − x1 ∆x
focal length of the lens is 10.0 cm or 15.1cm but be calculated upto proper decimal place or
10 cm is a wrong record.) significant figures as specified in the question
paper.
• All observations should be recorded with correct
units. (ii) All calculations should be rounded off upto
proper decimal place or significant figures, as
Graph work specified in the question papers.
Students should learn to draw graphs correctly noting
NOTE:
all important steps such as:
(i) Title Short answer type questions may be set from each
experiment to test understanding of theory and logic
of steps involved.

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Given below is a list of required experiments. 9. Verify Ohm’s law for the given unknown
Teachers may add to this list, keeping in mind the resistance (a 60 cm constantan wire), plotting a
general pattern of questions asked in the annual graph of potential difference versus current. Also
examinations. calculate the resistance per cm of the wire from
the slope of the graph and the length of the wire.
Students are required to have completed all
experiments from the given list (excluding 10. To determine the internal resistance of a cell by a
demonstration experiments): potentiometer.
1. To find focal length of a convex lens by using u- 11. From a potentiometer set up, measure the fall in
v method (no parallax method) potential (i.e. pd) for increasing lengths of a
constantan wire, through which a steady current
Using a convex lens, optical bench/metre scales is flowing; plot a graph of pd (V) versus length
and two pins, obtain the positions of the images (l). Calculate the potential gradient of the wire
for various positions of the object; f<u<2f, u~2f, and specific resistance of its material. Q (i) Why
and u>2f. is the current kept constant in this experiment?
Draw the following set of graphs using data from Q (ii) How can you increase the sensitivity of the
the experiments - potentiometer? Q (iii) How can you use the
above results and measure the emf of a cell?
(i) ν against u. It will be a curve.
Demonstration Experiments (The following
 v experiments are to be demonstrated by the teacher):
(ii) Magnification  m =  against ν which is a
 u 1. To convert a given galvanometer into (a) an
straight line and to find focal length by ammeter of range, say 2A and (b) a voltmeter of
intercept. range 4V.
(iii) y = (100/v) against x = (100/u) which is a 2. To study I-V characteristics of a semi-conductor
straight line and find f by intercepts. diode in forward and reverse bias.
3. To determine refractive index of a glass slab
2. To find f of a convex lens by displacement
using a traveling microscope.
method.
4. Identification of diode, LED, transistor, IC,
3. To determine the focal length of a given convex resistor, capacitor from mixed collection of such
lens with the help of an auxiliary convex lens. items.
4. To determine the focal length of a concave lens, 5. Use of multimeter to (i) identify base of
using an auxiliary convex lens, not in contact and transistor, (ii) distinguish between npn and pnp
plotting appropriate graph. type transistors, (iii) see the unidirectional flow
5. To determine focal length of concave mirror by of current in case of diode and an LED,
using two pins (by u-v method). (iv) check whether a given electronic component
(e.g. diode, transistors, IC) is in working order.
6. To determine the refractive index of a liquid by
using a convex lens and a plane mirror. 6. Charging and discharging of a capacitor.
7. To determine the focal length of a convex mirror PROJECT WORK AND PRACTICAL FILE –
using convex lens. 15 marks
8. Using a metre bridge, determine the resistance of Project Work – 10 marks
about 100 cm of (constantan) wire. Measure its
length and radius and hence, calculate the The Project work is to be assessed by a Visiting
specific resistance of the material. Examiner appointed locally and approved by the
Council.
All candidates will be required to do one project
involving some physics related topic/s under the

11
guidance and regular supervision of the Physics Suggested Evaluation Criteria for Theory Based
teacher. Projects:

Candidates should undertake any one of the  Title of the Project

following types of projects:  Introduction
 Contents
• Theoretical project
 Analysis/ material aid (graph, data, structure,
• Working Model pie charts, histograms, diagrams, etc.)
• Investigatory project (by performing an  Originality of work (the work should be the
experiment under supervision of a teacher) candidates’ original work,)
 Conclusion/comments
Candidates are to prepare a technical report including
title, abstract, some theoretical discussion, Suggested Evaluation Criteria for Model Based
experimental setup, observations with tables of data Projects:
collected, graph/chart (if any), analysis and  Title of the Project
discussion of results, deductions, conclusion, etc. The  Model construction
teacher should approve the draft, before it is  Concise Project report
finalised. The report should be kept simple, but neat
and elegant. Teachers may assign or students may Suggested Evaluation Criteria for Investigative
choose any one project of their choice. Projects:
 Title of the Project
 Theory/principle involved
 Experimental setup
 Observations calculations/deduction and graph
work
 Result/ Conclusions
Practical File – 5 marks
The Visiting Examiner is required to assess the
candidates on the basis of the Physics practical file
maintained by them during the academic year.

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