Transcript final Physics Board revision Part 1

Physics Board Revision
for Std. XII
By : Dr. Nitin Oke
Safe 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.
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—
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 cells
13. Arrow on wire indicating direction of current
14. 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.
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 .
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 numerical
QU2 :( 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)
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
Circular
Motion
Total Marks 4/5
Question may be of
1,2,3 or 4 marks
Circular Motion
1.
2.
3.
4.
5.
Questions for 2 marks
Define uniform circular motion. Why it is
called as periodic?
Define angular displacement, radius vector
Define angular acceleration, Centripetal
force
Obtain relation between velocity and
angular velocity of a particle in UCM
Obtain relation between linear acceleration
and angular acceleration of a particle in
circular motion
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 road
9. Distinguish between centripetal and
centrifugal force
10.Explain why centrifugal force is called as
pseudo force
11.Draw neat diagram of force acting on
vehicle moving along banked road
12.What is conical pendulum?
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 force
17.Derive an expression for centripetal
acceleration
18.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.
Important formulae of CM
1
n
T
aResultant  ac2  aT2  (r ω 2 ) 2  (r  ) 2
2π
ω
 2π n
T
  
v  ωr
h
v  r g tanθ  r g   r g
L
2
ω2  ω1  α t
ω2  ω1 2 π (n2  n1 )
1   2
1 2
α

  ω1t  αt  (
)t
t
t
2
2
v
2(KE)
2
a
 rω  v ω 
r
mr
2
(ω2 ) 2  (ω1 ) 2  2α
Gravitation
Total marks 3/5
Questions may be of
1,2,3,4 marks
Questions for 2 marks
1. 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
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
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.
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 surface
b) Orbiting at height h above the surface
Important formulae of gravitation
M1M2
FG
R2
VC 
GM
g 2
R
GM

(R  h)
(R  h) 3
T  2π
GM
 d
g d  g 1  
 R
gR2
 gh (R  h) 
(R  h)
4
G π R3 ρ
3
GMm
GMm
GMm
KE

TE


PE  
2(R  h)
2(R  h)
Rh
2GM
8
Ve 
 2gR 
G π R3 ρ
R
3
v  Vc falls in P, Vc  V  Ve thenE
v  Ve then P v  Ve then H
gh 
BE 
GMm
2(R  h)
GM
 R 

g


2
(R  h)
Rh
2
Rotational
Motion
Total marks 4/6
Possible questions
are of 1,2,3 or 4
marks
2 marks
1. Define
Rigid body and Moment of inertia
Radius of gyration and moment of inertia
2. Explain physical significance of MI
3. 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
6. Prove that torque equals product of angular
velocity and moment of inertia
7. State principle of
parallel axis theorem
Principle of perpendicular axis theorem
8. 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
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 5MR2/4
C. 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
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
Important formulae of MI
n

g

 mk rk
1
n
m
1

g

 rdm
 dm
n
I   mk rk   r 2 dm
2
k 1
MI of standered bodies
k
KERolling  KETrans  KERot
about respective axes
KERolling 
1
1
m v 2  I ω2
2
2
τ  Iα  I(
KERolling
1
1
2
2 v
 m v  mk 2
2
2
r
2
1
k2
2
 m v (1  2 )
2
r
ω2  ω1
)
t
Oscillation
Total marks 5/7
Possible questions may be of
1,2,3 or 4 marks
2 marks question
Define
1.
2.
3.
4.
5.
6.
Periodic motion, Linear SHM
Phase of a particle performing SHM
Amplitude, Period for particle in SHM
Angular SHM, force constant
Phase and epoch
Second’s pendulum, simple pendulum
7. State the expression for KE and write
values for KE at mean position and
extreme position
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
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
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
4 marks question
1. 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.
Important formulae of Oscillation
d2 x
k
2


x

ω
x
2
m
dt
x  Asin( t   )
2
2
V  A cos( t   )   A  x
2
2
a  - A sin( t   )    x
1
1
2
2
2
2
2
KE  m (A - x )  k(A - x )
2
2
1 2 2 1 2
1 2 2 1 2
PE  m x  kx
TE  m A  kA
2
2
2
2
Important formulae of Oscillation
m
1
T  2π
 2π
k
acc. per unit displaceme nt
L
T  2
simple pendulum
g
for second' s pendulum T  2, L 
I
T  2
bar magnet
MB
g

2
Elasticit
y
Total Marks 4/6
Possible questions are of
1,2,3 or 4 marks
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 units
4. Define stress, strain and their dimension
5. What is shearing stress? State its units and
dimension
6. 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
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
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 point
16.Explain why two identical wires of the
same material used in method for the
determination of Y
Questions for 3 marks
18. Define strain and explain its different
types
19. 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.
Questions for 4 marks
1. Derive expression for work done per unit
volume in stretching a wire
2. With the graph explain behavior of a wire
under increasing load
3. Prove that strain energy per unit volume
equals (stress x strain)/2
Important formulae
FL MgL
Y

A x π r2x
MgL
x
2
πr Y
dP
VdP
K

dV
( V V )
F

A
(d D) dL
  x 
( L ) Dx
1
W  (stress )  (strain )
2
Y
1
2
2
 (strain ) 
(strss )
2
2Y
1
1
2
 F  k
2
2

3
WL
4bd3 Y
Thermal Stress = Y( )
Surface Tension
Total marks 4/6
Question may be of
1,2,3 or 4 marks
Questions of 2 marks
1. Define Range of molecular attraction,
sphere of influence
2. Define Angle of contact, surface tension
3. Define Cohesive force, Adhesive force
4. Obtain dimension of surface tension and
state its units
5. State four characteristics of angle of
contact
6. Give applications of surface tension.
7. Give applications of capillary action.
8. State Laplace’s law of spherical membrane.
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
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.
Important formulae of properties of liquid
hr ρg
T
2 cosθ
W  T AF
F  2 T LF
2T
P 
for drop or bubble in liquid
r
T3
T2  T1
cos 
T3
T2
T
2T cosθ
h
rρg
r 2T cosθ
h+ 
3
rρg
4T
P 
for bubble in air
r
1
when R  n r
1
E=4R2T(n 3
 1)
2
 n3 )
=4r2 T(n
1 1
3
=4R T(  )
r R
Wave Motion
Total marks 3/5
Questions may be of
1,2,3 or 4 marks
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 wave
4. State any four characteristics of longitudinal
wave
5. State any four characteristics of Transverse
wave
6. Distinguish between Transverse and
Longitudinal waves
7. State and explain principle of superposition of
sound waves with the help of constructive and
destructive interference
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.
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.
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.
Important formulae for wave mechanics
2 π x

y  A sin ω t 

λ 

x

y  A sin2  n t  
λ

2πx
δ
λ
AR  A12  A22  2A1A2 cosφ
beat frequency n1  n2
 1 .2
Vw  beat frequency  
 
2
1

x


y  A sin2π n  t  

v


 n1  n 2  
 n1  n 2 
y  2A cos2π
 t  . sin2π
t
 2  
 2 

x
 t
y  A sin2   
 T λ
2
vt  x 
y  A sin
AR



Stationary Waves
Total marks 5/7
Questions may be of
1,2,3 or 4 marks
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
overtone
6. State expression for frequency of vibrating
string hence show that n is inversely
proportional to radius and root of density of
wire
7. Explain resonance
8. Explain forced and free vibrations
9. Describe construction of Sonometer
10.What is end correction? How to estimate
end correction?
11.State any two laws of vibrating string
12.Draw Diagrams showing parallel and
perpendicular position
13.Draw Fundamental mode of vibrating air
columns in open and close pipe
14.Draw First and second harmonics of
string
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
3 marks questions
1. 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
3 marks questions
4. 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.
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
Important formulae for Stationary waves
2πx
2πt
Y  2Acos
.sin
 fromfreewall
 λ 
 T 
2πx
2πt
Y  2Asin
.cos
 fromrigidwall
 λ 
 T 
p T
p
T
p
T
p T
n


N F  2n 
2
2L m 2L π r ρ 2Lr  
 m
(2N 1)V (2N 1)V (2N 1) γP
n


4L
4(  0.3d)
4L
ρ
NV
NV
N γP
p T
n


N F n 
2L 2(  0.6d) 2L ρ
2 m
Kinetic theory of
gases and Radiation
Total marks 4/6
Possible questions may be of
1,2,3 or 4 marks
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 KTG
5. 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 heats
7. Explain Cp greater than Cv
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 gas
13.Define principle specific heats of gas
14.Define internal latent heat.
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.
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.
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
3 marks questions
1. Define coefficient of absorption, emission
2.
3.
4.
5.
and transmission and obtain relation
between them.
What do you mean by perfectly black body?
Can it be realized in practice? How will you
construct perfectly black body?
Give theoretical proof of equality of
emissive and absorptive power.
State Stefan’s law, Newton’s law and
Kirchhoff’s law.
Obtain Newton’s law using Stefan’s law.
Questions for 3 marks
1.Using specific heat capacities show
that adiabatic constant of ( any one )
1.monatomic gas is 5/3
2.( Rigid) Diatomic gas is 7/5
3.(Non rigid) Diatomic gas is 9/7
4. Polyatomic gas (4+f)/(3+f)
2. State zeroth, first and second law
of thermodynamics.
Questions for 4 marks
1. 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.
Expression for terms used in KTG
Useful relations for problems:
C1
2

C2
1
( if pressure is constant)
M2
M1
(it temperature is
constant)
T1

T2
(if gas is same)

C1
T1 M 2
( if gas and temperature is

x
C2
T2 M1 different )
c1  c2  c3        cN
c 
N
2
2
2
2
c1  c2  c3        cN
2
c 
Crms
N
3PV
3nRT
3kT
3RT
3RT
3kN0T






M
M
M0
mN0
M0
m
1 2
P  c
3
1 M 2 1 N.m 2
P
c 
c
3V
3 V
mean free path  
KT
2.d P
2

1
2.d 2n
KE
3
 P
Volume 2
Molar specific heat CP  M0cP
Molar specific heat CV  M0cV
KE
3
 RT
mole 2
KE
3 RT 3

 KT
molecule 2 No 2
KE
3 RT

mass 2 M
R
cP  cV  r 
Mo
PdV
L  LI 
J
7
cal
kcal 4.2x10 erg 4200J



gram.K kg.K
gram.K
kg.K
Important formulae for Radiation
a
heat absorbed
heat incident
heat reflected
r
heat incident
t
heat transmited
heat incident
a+r+t=1
Qemitted  e..AtT 4
Qabsorbed  e..AtT0 4
Qnet exchange  e..At(T 4  T0 4 )
Q
E
at given temperatur e
A.t
E
e
where both are at same temperatur e.
Eb
2  1
1  2


dQ
d d

k


 m.s.
 K(  o )
o

t2  t1
 2

dt
dt dt