Physics Board Revision for Std. XII

By : Dr. Nitin OkeSafe Hands, Akola

Note these General and essential Points - - -

1. It is essential to give question number and sub question number in the margin provided.

2. Next question ( NOT SUBQUESTION) must start on next page.

3. Draw relevant diagrams even if not asked.

4. All figures must be drawn by pencil. They must be labeled and sufficiently large.

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Note these Points - - -

7. While solving numerical problems first write given data convert it into S.I. units. Write the formula needed and substitute the values. Do calculations using log or direct in a box call it as rough work ( it should be neat and good looking)

8. The answer of numerical problem must be with units and should be in a box.

9. While deriving any expression remember that your next step is outcome of previous step.

10. If you want to cancel some part don’t cancel it as“Parallel axis theorem : If Iz is MI about an axis perpendicular it should be as—

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Points you need to remember

11.Diagrams must be labeled and arrow must be shown for current and vectors. The key must be introduced and polarities of A, V, source, must be shown.

12.Show polarity of cells13.Arrow on wire indicating direction of current14.Remember to show variable resistance

(rheostat), key, Galvanometer, source of e.m.f. with polarity ( take proper care when used in potentiometer)

15.All most every definition must be with example.16. If question is about comparison or assumptions

then just give the list of points.Safe Hands

Points to remember

17.While doing numerical problems of meter bridge or Whetstone's network better have figure.

18.When ac is applied direction of current is not to be showed

19.Remember to indicate transformer, primary, secondary, load resistance, “e” input ac voltage, Vo output voltage, if full wave rectifier then center tap, direction of current in load resistance connected to output.

20.Once you note down data in SI units think about formula needed and use it .

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PAPER “Physics” BOARD PATERN IS

Single Paper of 3 hours with total marks 70 =35 ( section I ) + 35 (Section II) Passing will be at 18 ( Useful for NEET students)QU1 : ( 7 marks) one will be numericalQU2 :( 12 marks) 2 marks each solve any

6 /8(at least 4 numerical problems)

QU 3:( 9 marks) 3 marks each solve any 3 from 4

(at least 1 numerical problems)QU 4: (7 marks) 7 marks each solve any 1 from

2(subpart with at least 2 or 3 numerical

problems)

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IN SHORT IN PHYSICS PAPER WILL CONSIST OF

1. 12 MCQ based on theory 2 MCQ based on numerical in all 14 MCQ

2. 16 short answer questions of 2 marks each with 8 numerical from which you need to solve 12 means 12 short answer questions

3. Two 3 marks and 1 four mark question with less choice 2 from QU 3 and 1 from QU 4. with 3 numerical of 3+ 4 or 3 marks. Means in Paper of Physics 25 marks will be numerical

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Circular Motion

Total Marks 4/5Question may be of

1,2,3 or 4 marks

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Circular Motion

Questions for 2 marks1. Define uniform circular motion. Why it is

called as periodic?2. Define angular displacement, radius

vector3. Define angular acceleration, Centripetal

force4. Obtain relation between velocity and

angular velocity of a particle in UCM5. Obtain relation between linear

acceleration and angular acceleration of a particle in circular motion

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6. What is banking of road?Is the safe speed limit is same for all vehicles? why?

7. Derive expression for maximum speed where the curved road is not banked

8. Explain the need of banking of road9. Distinguish between centripetal and

centrifugal force10.Explain why centrifugal force is called as

pseudo force11.Draw neat diagram of force acting on

vehicle moving along banked road12.What is conical pendulum?

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13.Define angular velocity, angular acceleration and give their directions

14.Define angular velocity, angular acceleration and give their SI units

15.Define UCM and obtain relation between linear and angular velocity

16.Explain centripetal and centrifugal force17.Derive an expression for centripetal

acceleration18.Define angle of banking and obtain

expression for the same.19.Write Newton’s equations for rotational

motion.20.Obtain expression for time period of conical

pendulum.Safe Hands

Important formulae of CM

T1

n

n 2πTπ 2

ω

rωv

tt

)n(n π 2ωω 1212

α

mr2(KE)

ω vrωrv

a 22

2222T

2cResultant (r )ω(r aaa )

gr Lh

gr tanθ gr v 2

tα ωω 12

α2)() 22 12 ω(ω

tαtt )2

(2

1 212

1ω

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GravitationTotal marks 3/5

Questions may be of 1,2,3,4 marks

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Questions for 2 marks1. State Newton’s law of gravitation, give

SI unit and dimensions of constant of gravitation

2. Obtain relation between gravitation constant and gravitational acceleration at certain height from surface of earth

3. Obtain relation between gravitational acceleration at certain height from surface of earth and on surface of earth

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4. Explain why two stage rocket is necessary to launch a satellite

5. State the conditions under which satellite will move in parabolic and elliptic path

6. Derive the expression for critical velocity of a satellite.

7. Derive an expression for period of a satellite revolving round the earth

8. Explain communication satellite and give its two applications

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9. Define escape velocity and binding velocity

10.Obtain expression for binding energy of a body at height h above the surface of earth when it is at rest

11.Obtain expression for escape velocity of the satellite on surface of earth

12.Explain weightlessness

13.State Kepler’s laws of motion

14.Draw and explain the graph of ‘g’ and distance from centre of earth.

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For 4 marks

1. Define critical velocity and obtain expression for it and state the factors on which it depends

2. Obtain expression for critical velocity of a satellite at height h and obtain expression for period

3. Define binding energy and obtain expression for the same

a) at rest on earth surfaceb) Orbiting at height h above the surface

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Important formulae of gravitation

221

R

MMGF 2R

GMg

2

2h hRR

gh)(R

GMg

Rd

ggd 1

ρR πG 34

h)(Rgh)(R

gRh)(R

GMV 3

h

2

C

GMh)(R

2πT3

ρR πG 38

2gRR

2GMV 3

e

hRGMm

PE

h)2(R

GMmKE

h)2(RGMm

TE

h)2(RGMm

BE

Hthen V vPthen Vv

thenEVVV P,in fallsVv

ee

ecc

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Rotational Motion

Total marks 4/6

Possible questions are of 1,2,3 or 4 marks

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2 marks

1. DefineRigid body and Moment of inertiaRadius of gyration and moment of inertia

2. Explain physical significance of MI3. Compare MI of solid sphere and hollow

sphere of same mass and of same material

4. Show that total KE of a sphere of mass m rolling along horizontal plane with velocity v is 7mv2/10 and similar

5. Deduce an expression of KE of rolling body Safe Hands

6. Prove that torque equals product of angular velocity and moment of inertia

7. State principle of parallel axis theorem Principle of perpendicular axis

theorem8. Show that MI of thin uniform rod about an

axis passing through a point midway between center and edge, perpendicular to it is 7ML2/48 ( and similar)

9. Using parallel axis theorem and MI of axis of length L, mass m about an axis perpendicular to rod is ML2/12 obtain MI about an axis perpendicular to rod and through edge

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10.MI of solid sphere about its diameter is 2MR2/5 with usual meaning then determine MI about tangent

11. Assuming MI of a uniform disc about an axis passing through its center and perpendicular to its plane,

A. obtain an expression for its MI about any diameter

B. show that MI about tangent is 5MR2/4C. Show that MI about axis passing through edge

and perpendicular to plane of disc is 3MR2/2

12.State the principle of conservation of angular momentum and explain it with suitable example

13.State and prove law of conservation of angular momentum Safe Hands

3 marks each

1. Define radius of gyration and give its physical significance

2. State and prove principle of parallel axis about moment of inertia

3. State and prove principle of perpendicular axis about moment of inertia

4. Derive expression for MI of a rod of mass M and length L about an axis passing through its center and perpendicular to it, hence obtain MI about an axis perpendicular to it and passing through one of its edge

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Important formulae of MI

n

1k

n

1kk

m

rmg

dm

dmrg

dmrrmI 2n

1k

2kk

RotTransRolling KEKEKE 22

Rolling ω I21

vm21

KE

)ωω

I(I α 12

tτ

)1(2

22

2

222

Rolling rk

vm21

rv

mk21

vm21

KE

axes respectiveabout

bodies standered of MI

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OscillationTotal marks 5/7

Possible questions may be of 1,2,3 or 4 marks

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2 marks question

Define

1. Periodic motion, Linear SHM2. Phase of a particle performing SHM3. Amplitude, Period for particle in SHM4. Angular SHM, force constant5. Phase and epoch6. Second’s pendulum, simple

pendulum7. State the expression for KE and write

values for KE at mean position and extreme position Safe Hands

8. Show that PE of a particle is directly proportional to the square of its displacement from mean position

9. Assuming expression for KE and PE of a particle performing SHM obtain expression for TE and deduce conclusion from it.

10.Define second’s pendulum and show that length of seconds pendulum is constant at given place

11.Deduce an expression for period of a particle performing SHM in terms of force constant

12.Draw diagram showing displacement and velocity against time

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13.Obtain expression of velocity using differential equation of SHM

14.Obtain expression for period of simple pendulum

15. State differential equation for angular SHM give one example for the same.

16. Represent KE and PE against displacement in separate graphs with proper labeling

17. Write down at what distance from mean position the KE =PE and at what distance velocity will be half of maximum Safe Hands

3 marks question

1. Show that linear SHM can be considered as the projection of UCM on any diameter

2. Represent graphically the displacement, velocity and acceleration against time for a particle performing linear SHM when it starts from extreme position

3. Assuming general equation of displacement in SHM obtain expression for velocity and acceleration

4. Obtain expressions for KE,PE and hence show that TE is constant for linear SHM

5. Discuss analytically, the composition of two SHMs of same period and parallel to each other Safe Hands

4 marks question1. State the differential equation of SHM and

obtain expression for displacement, velocity and acceleration

2. Obtain expression for period of simple pendulum, hence calculate the length of second’s pendulum

3. Obtain expression for the period of a magnet vibrating in a uniform magnetic induction

4. If x1 = a1sin(t+1) and x2=a2sin(t + 2) obtain an expression for resultant amplitude hence obtain resultant amplitude when phase differ by 0o and by 90o. Safe Hands

Important formulae of Oscillation

xω -xmk

dtxd 22

2

) Asin( x t22 xA) cos( A V t

xt 22 ) sin(A- a

)x-k(A21

)x-(Am21

KE 2222 2

22 kx21

xm21

PE 2 22 kA21

Am21

TE 2

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Important formulae of Oscillation

ntdisplacemeunit per acc.1

2πkm

2πT

2

gL 2, Tpendulum ssecond'for

pendulum simple Tg

L2

magnetbar MBI

T 2

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ElasticityTotal Marks 4/6

Possible questions are of 1,2,3 or 4 marks

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Questions of 2 marks

1. What is elasticity? How can you differentiate between elastic body and plastic body?

2. Define deforming force and perfectly elastic body

3. Define stress and strain, write their units4. Define stress, strain and their dimension5. What is shearing stress? State its units and

dimension6. The graph of stress against strain

is as shown in adjoining figure,state what points E,Y and C represents, define any one of them

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7. Define bulk modulus & derive expression for it.

8. What is elastic limit? What happens beyond elastic limit?

9. State Hooks law of elasticity and define modulus of elasticity

10.Explain why only solids posses all the three constants of elasticity

11.Deduce an expression of Young’s modulus of material of a long uniform wire

12.Assuming Hook’s law show that Young’s modulus of the material of a wire is the stress required to double the length of wire Safe Hands

13.Define modulus of rigidity and derive its necessary formula

14.Prove that deforming force is directly proportional to the change in the volume of a wire in the case of Young’s modulus

15.Define Yield point, Breaking point16.Explain why two identical wires of the

same material used in method for the determination of Y

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Questions for 3 marks18. Define strain and explain its different

types19. What is Poisson’s ratio? Why it does

not have any unit?20.Give the expression of sag of horizontal

beam and explain terms used in it.21.How will you relate ductility and

brittleness with stress strain graph. Give examples of both types.

22.Define thermal stress and relate it with coefficient of linear expansion and Young’s modulus.

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Questions for 4 marks1. Derive expression for work done per

unit volume in stretching a wire2. With the graph explain behavior of a

wire under increasing load3. Prove that strain energy per unit

volume equals (stress x strain)/2

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Important formulae

xr π

L g M

xL

AF

Y 2

Yr π

L g Mx 2

dVVdP

)VV(

dPK

AF

DxdL

L x

D d

)(

)(

2

22

2

1

2

12

1

2

kF

)strss(Y

)strain(Y

)strain()stress(21

W

3

3

WL

4bd Y

Thermal Stress = Y ( ) Safe Hands

Surface Tension

Total marks 4/6Question may be of

1,2,3 or 4 marks

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Questions of 2 marks

1. Define Range of molecular attraction, sphere of influence

2. Define Angle of contact, surface tension3. Define Cohesive force, Adhesive force4. Obtain dimension of surface tension and

state its units5. State four characteristics of angle of

contact6. Give applications of surface tension.7. Give applications of capillary action.8. State Laplace’s law of spherical

membrane.Safe Hands

3 marks questions

1. Explain formation of concave and convex surface on the basis of molecular theory

2. Explain why angle of contact is acute for water – glass interface and is obtuse for mercury –glass pair

3. Explain the term angle of contact, What is the nature of an angle of contact for a liquid which partially wets and does not wet the solid

4. State expression for rise of liquid in capillary tube and explain the factors affecting the rise of liquid

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4 marks questions

1. Explain surface tension on the basis of molecular theory

2. What is surface energy? Establish relation between surface tension and surface energy

3. Using molecular theory explain why the free surface of some liquids in contact with a solid is not horizontal

4. What is capillarity? How it is used to determine surface tension of a liquid which wets the glass.

5. State Laplace’s law of spherical membrane and prove it. Safe Hands

Important formulae of properties of liquid

cosθ 2g ρr h

T

FAT W

FL T 2F

4TP f or bubble in air

r

2TP f or drop or bubble in liquid

r

2 1

3

T Tcos

T

T1T2

T3

2T cosθ h

r ρ g

r 2T cosθ h+

3 r ρ g

12 3

22 3

3

when R n r

E=4 R T(n 1)

=4 r T(n n )

1 1 =4 R T( )

r R

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Wave MotionTotal marks 3/5

Questions may be of 1,2,3 or 4 marks

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Questions of 2 marks

1. Wave is doubly periodic phenomenon, explain

2. State any four characteristics of simple harmonic progressive wave

3. Define Longitudinal, Transverse wave4. State any four characteristics of longitudinal

wave5. State any four characteristics of Transverse

wave6. Distinguish between Transverse and

Longitudinal waves7. State and explain principle of superposition

of sound waves with the help of constructive and destructive interference Safe Hands

8. What are the conditions for beat formation

9. What are beats? State two applications of beats

10.What is Doppler's effect? State any two applications

11.Draw neat labeled diagram of Quincke's tube.

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Questions for 3 marks

1. Obtain equation of simple harmonic progressive wave in positive direction of X axis

2. Explain the phenomenon of reflection of sound waves from denser medium and from rare medium

3. Explain the phenomenon of reflection of transverse waves from denser medium and from rare medium

4. State and explain principle of superposition of waves

5. Explain method of determination of wavelength of sound using Quincke’s tube.

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Questions for 4 marks

01. Obtain expression for progressive wave and write it in two different form

02. Using analytical treatment show that the beat frequency is equal to difference between frequencies of interfering waves.

03. Describe construction of “ Quincke’s tube” and how it works?

04. Explain Doppler's effect in sound. Give mathematical expression for frequency

and its application.

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Important formulae for wave mechanics

λ xπ 2

t ωsin Ay

λ

x t nsin2 Ay

λ

x Tt

sin2 Ay

xvt2

sin Ay

vx

t n sin2 Ay π

λ xπ 2

δ

φcosA2AAAA 2122

21R

21 nn frequencybeat

1 2w

2 1

.V beat f requency

t2

nn sin2π . t

2nn

cos2 2Ay 2121

π

AR Safe Hands

Stationary WavesTotal marks 5/7

Questions may be of 1,2,3

or 4 marks

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2 mark questions

1.What are stationary waves and why they are called so?

2.State any four characteristics of stationary waves

3.What are the conditions of stationary waves?4.What are nodes and antinodes?5.State the difference between harmonics and

overtone6.State expression for frequency of vibrating

string hence show that n is inversely proportional to radius and root of density of wire

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7. Explain resonance8. Explain forced and free vibrations9. Describe construction of Sonometer10.What is end correction? How to

estimate end correction?11.State any two laws of vibrating string12.Draw Diagrams showing parallel and

perpendicular position 13.Draw Fundamental mode of vibrating

air columns in open and close pipe14.Draw First and second harmonics of

string

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12.Distinguish between Harmonics and overtone

13.Distinguish between stationary and progressive waves

14.Distinguish between free and damped vibrations

15.State the formula for fundamental frequency of string explain terms used

16.State the formula for fundamental frequency of vibrating air column in open pipe and explain terms used

17.State the formula for fundamental frequency of vibrating air column in pipe closed at one end and explain terms used

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3 marks questions1.Using analytical method derive

expression for resultant displacement of two progressive waves traveling in opposite directions. Why it is called as stationary wave.

2.Explain vibration of stretched string fixed at two ends.

3.State the formula for fundamental frequency and explain laws of vibrating string

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3 marks questions4. Explain why all harmonics are

present in air vibrating in a pipe open at both ends and not in pipe close at one end.

5. Explain the terms forced vibration and Resonance and give two applications of resonance.

6. Explain the working of flute.7. Explain working of harmonium.

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Questions of 4 marks

1.Describe Melde’s experiment to determine frequency of tuning fork in perpendicular position.

2.Describe Melde’s experiment to determine frequency of tuning fork in parallel position.

3.Explain how velocity of sound can be measured using resonance tube

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Important formulae for Stationary waves

wall free fromT

t 2.sin

x 22AcosY

π

λ

π

wall rigid fromT

t 2.cos

x 22AsinY

π

λ

π

T

2Lrp

r T

2Lp

mT

2Lp

n 2 ρ π

ργP

4L1)(2N

0.3d)4(1)V(2N

4L1)V(2N

n

ρ

γP2LN

0.6d)2(NV

2LNV

n

mTp

2n N F

mTp

n N F 2

Kinetic theory of gases and Radiation

Total marks 4/6Possible questions may be

of 1,2,3 or 4 marks Safe Hands

Questions for 2 marks

1. Explain the terms free path, mean free path

2. Explain cause of pressure on close container

3. Define mean square velocity, root mean square velocity

4. Deduce Boyle’s law on the basis of KTG5. Assuming the expression for pressure

exerted by the gas show that kinetic energy per mole of gas is 3RT/2N

6. Explain why gases have two specific heats7. Explain Cp greater than Cv

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Questions for 2 marks

9. Assuming the expression for pressure exerted by the gas show that P.V=2(TKE) / 3

10.Define ideal gas.11.Show that KE per unit volume of a

gas is directly proportional to atmospheric pressure.

12.Define molar specific heats of gas13.Define principle specific heats of gas14.Define internal latent heat.

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2 mark questions

1.Define coefficient of absorption and reflectance.

2.Define coefficient of absorption and of transmission.

3.Obtain relation between a, r and e.4.Define coefficient of transmission. If t = 0

then what type of body it is? give example.5.Explain construction and working of perfectly

black body.6.What do you mean by black body. State the

use of conical projection of an artificial black body.

7.Define emissive power and emissivity of body. Safe Hands

2 mark questions

8. Define emissive power and list the factors on which it depends.

9. State Kirchhoff's law of radiation and Stefan’s law of radiation.

10.State Stefan's law for radiation. Write unit of Stefan's constant.

11.State Wien's law of radiation. Write unit of “b”

12.State the limitations of Newton’s law of cooling.

13.State Prevost’s theory of heat exchange.

14.Write two observations of energy diagram of black body radiations.

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Questions for 3 marks

1.State any two assumptions of Kinetic theory of gases and show that RMS velocity is directly proportional to square root of absolute temperature.

2.State any two assumptions of KTG and obtain Boyle’s law.

3.Define principle specific heats and explain why cp > cv

4.What are degree of freedom and state law of equipartition of energy.

5.State Dalton’s law and Charle’s law

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3 marks questions

1. Define coefficient of absorption, emission and transmission and obtain relation between them.

2. What do you mean by perfectly black body? Can it be realized in practice? How will you construct perfectly black body?

3. Give theoretical proof of equality of emissive and absorptive power.

4. State Stefan’s law, Newton’s law and Kirchhoff’s law.

5. Obtain Newton’s law using Stefan’s law.

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Questions for 3 marks

1.Using specific heat capacities show that adiabatic constant of ( any one )1.monatomic gas is 5/32.( Rigid) Diatomic gas is 7/53.(Non rigid) Diatomic gas is 9/74. Polyatomic gas (4+f)/(3+f)

2. State zeroth, first and second law of thermodynamics.

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Questions for 4 marks1. Write any eight assumptions of KTG.2. On the basis of KTG obtain expression

of pressure exerted by enclosed gas.3. Draw and explain the curve between

energy and wavelength of radiations by a black body at different temperatures.

4. State Kirchhoff’s law and give its experimental explanation.

5. State & explain Prevost’s theory of heat.

6. Derive Newton’s law of cooling using Stefan’s law.

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Expression for terms used in KTG

Useful relations for problems:

1

2

2

1

C

C

( if pressure is constant)

1

2

M

M (it temperature is

constant)

2

1

T

T (if gas is same)

( if gas and temperature is different ) 1

2

2

1

2

1

M

Mx

T

T

C

C

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2

3

1cP 22

3

1

3

1c

Vm.N

cVM

P

M3PV

Crms 0M

3RT

M3nRT

0mN

3RT

m3kT

0

0

MT3kN

N

ccccc N

223

22

212

N

ccccc N321

nd.Pd.

KT path free mean

22 2

1

2

Safe Hands

P2Volume

EK 3

RT2mole

EK 3

KT2N

RT2molecule

EK

o

33

MRT

2massEK 3

J

PdVLL I

PP cMC heat specific Molar 0

VV cMC heat specific Molar 0

oVP M

Rrcc

K.kgJ

K.gram

ergx.

K.kgkcal

K.gramcal 42001024 7

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Important formulae for Radiation

incident heatabsorbed heat

a

incident heatreflected heat

r

incident heattransmited heat

t

a + r + t = 1 etemperatur given at t.A

QE

e.temperatur same at are both where EE

eb

4AtT..eQemitted

40AtT..eQabsorbed

)TT(At..eQ exchange net40

4

dtd

.s.mdtdQ

)(Kdtd

o

oktt 2

21

12

12

Safe Hands