XI SESSION ENDING EXAM 2011-12

1. TimeAIIowed:3 Hours
KENDRIYA VIDHYALAYA SANGATHAN JAIPUR REGION
SESSION ENDING EXAMINATION 2O1L-12
Class ; XI
SUBJECT: PHYSTCS
Maximum Marks : 70
l
General Instructions -
(a) All questions are compulsory.
(b) There are 30 quesrions in totar. euestions t to g carry one rrt,rk
carry two marks each, questions lg to 27 carry three mqrks cach
carry.five marks each.
each, questions 9 to IB
and question,s 28 to 30
(c) There is no overall choice. However, an internql choice has been provided in one question oftwo marks, onte question of three mqrks and all three questinn" o6u" *orn, eqch. you hove
to afiempt only one of tlie given choices in such questions.
(d) Use of calculators is not permitted.
(e) You may use the followin-g physicar constants wherever necessqry:
c -- 3 x ldms-'G:6.67 x 10-tt Nm2kg-2g: 9.g m/s2Boltr*onr-"onstant k: l.3g x l0z3JK)
Avogadro's number N,t: 6.023 x lds/moreRodius of Earth R:6400Km
[$]--Narne four firnrJamental forces in nature in descending order of their magnitude.
|/low is the force of friction important for a ear to get accelerated?
-)''Doe" the centre of mass of a body necessarily lie inside the body? Also give an example
-A1 fne motion of a particle of nrass m is described by y : u t + ,/z gt2.Find the force acting on
,t ,.
the particle.
-1
-54 Deps,Oower and write its SI unit.
56.-ffiatis the value of escape velocity at the surface of earth?
",-Whetimeperiodofsimplependuluminanartificialsatellite?
V*,,yplacement and accereration be in same direction in S.H.M.?
*;W frequency of vibration v of a mass m suspended from a spring of spring constant. k is
, given by a relation of the type v : c nf tr/ where L i= u dimensionless'constant. calculate
the x and y.
if each of the following statements is true or false. Give reasons for your answer.
(a) In an- elastic. collision of two bodies, the momentum and energy of each body is
conserved.
(b) work done in the motion of a body over a closed loop is zero for every force in nature.
fl)efrne
gravitational potential energy and write the relation between gravitational potential
' Y-nd gravitatio;raf potential energy.
?.Firy{shows the position-time graph of a particle of,mass 4 kg. What is the impulse at t - O
1

2. *y
t (s)
with
-fl3Jrff;':ffi:".fft-itv at constant press.re greater than the
+
t 7- At whE tqptrarurc is &e root
equal to the rms speed;;
m9a1 squarc sped of a molecule in i
'Zr-
t gas molec'l"ut- to "c? *t'""r*;":::il;'fi;
y.fiy"oefficient of viscosity and write its sI unit.I2-t46env€ a relarinn r.^r-.^-*oyyua reration berween rmpurse J;;;omentum.
)W-{PA"es a sricketer lowers his hr
t-M^4h aa---^--. ^
rnds while catching aball?
ffi;-TJ*-fi.ont*um
speed *itr'which;;;;"* saGry negotiate a curved
#,fii*ff ;:::.I;H X .::".,.1-.;^t:*,
Gi ve the dependence or mean rree path
of mol*lesbf a gas on pressure *o o
' "rv'rut rf,' Li
?) -( a^-!__ r . :mperature of gas.p-K spr&g having wi& a spring
""**-rloo"f ;,showq in Figure. A mass of,3 ko i< a+i_^L^.r __ ., ^
rs mounted on a horizontal table as
;ffi;::ilH ffi:: :f I":1; i ffij # ff: #ffj:iJH;pulled sideways to a distance of 2.0 cm and released.
Determine (i) the of oscillations, (ii) maximr hcceleration of the mass,gnd (iii)
,',,
qA-,-
'2 (.
%
'Y"'2
-v"
molar specific
ty{,,'tve tJre equation of motions = ui * !ot"
by using carcurus method.
W
moment of ineftia and write its prrysical significance.
t/fu" 1e
the necessary conditions for a ooton;*^ ._
- ---v 'vvvosary Condttions fof a sat lli+o +^ _,,
otyzdthe earth's surface?
: a satellite to appear stationary
23.,,Define Isothemral.process
and derive an
^-/
process. expression for work done during Isothermal
q

3. 25.(a) Find the moment of inertia of a sphere about a tangent to the sphere, given thi moment of
inertiaof thesphgreaboutanyof itsdiametersto be?ptn' ,whereMisthemassof the
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at are conservative and non-conservative forces? Give one exurmple of each.
'
sphere and R is the radius of the sphere.
(b) Given the moment of inertia of a disc of mass M and radius R about any of its diameters
,o a.l un' , find its momer$ of inertia about an axis normal to the disc and passing through
4
a point on its edge-
OR
for the excess pressure inqide a liquid drop.
parallelogram law of vector addition. Find the relations for magnitude and direction of '
{
.y
AJ
range and maximum height are equal,-the angle of projection is tan-r 4.
lli's theorem. Using it how e€u1 you explain the firnctioning of a venfurirneter
find the velocity of flow and rate of flow of liquid through a tube?
r.elocity
OR
derive its expression. Also draw
What do understand by the phenomenon of beats? Discuss the
a graph betweerr terminal
30. formation of beats
difference of ttreanalyt and hence prove that the beat frdquency is equal to the
ies of the two waves superposing.
sitar_sgings A and B playing the note 'Ga' are slightly out of tune and produce beats of._,,-a-r,_,.. . ^ +
qfleuencyjift)The tension in the striqg A i-s. slightly red-uqed ugd thq beaJfreguency is-.-::--+-F.-ft*r:---*ffi
fotrnd to reduce tol.@:. If the original frequency of A is B24Hz,whai'is thethe frequency of
Establish the relation between torque and angular acceleration. Hence define moment of
inertia,n
.r'
. 26;O{ive an expression for the centripetal acceleration of a particle moving with uniform speed
V* T along a circular path of radius r. Discuss the direction of this acceleration.f valwt
9N"yz
resultant vector.
Prove that
OR
(a) For two angles of projectiono and (gO-e)with same velocity of projection,
(i) Horizontal Range is same (ii) Heights are in the ratio t:rnz e : l.
5 B?

4. a simple
t
4
f, ,'li.:
,i:
... rr -*
-;=*;*.*** ...-. "+:-=ga1,=n- ...,-i-,=--u**,
f
,. -j
ii I
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MAHENDRA SINGH PGT PHYSICS
KV 1 AFS,JODHPUR
msr.phy20@gmail.com
www.mahenphysics.com