HBSE Class 12 Sample Paper 2024 Physics

HBSE
MODEL PAPER
2024
Practice Papers
MODEL PAPERS
Marking Scheme
ANSWER KEY

Class: XIISESSION:2023-2024
HBSE SAMPLEQUESTIONPAPER(THEORY)
SUBJECT:PHYSICS

MaximumMarks:70Marks TimeAllowed:3hours.

GeneralInstructions:

(1) There are35 questionsin all. Allquestionsarecompulsory
(2) This question paper has five sections: Section A, Section B, Section C,
SectionDandSection E.Allthese Sections arecompulsory.
(3) Section A contains eighteen MCQ of1 mark each, Section B contains
sevenquestions of two marks each, Section C contains five questions of three
markseach, section D contains three long questions of five marks each and
Section Econtainstwocase studybased questions of4marks each.
(4) There is no overall choice. However, an internal choice has been provided
insection B, C, D and E. You have to attempt only one of the choices in
suchquestions.
5.Useofcalculatorsis not allowed.

SECTIONA

Q. MAR
NO. KS
1 The electric potential on the axis of an electric dipole at 1
adistance‘rfrom it’scentre is V. Then the potential at a
pointatthesamedistanceonits equatorial linewill be
(i) 2V
(ii) -V
(iii) V/2
(iv) Zero
2 Resistanceof conductordoes notdependon 1
(i) Length ofconductor
(ii) Natureofmaterial
(iii) Radiusofcross sectionofconductor
(iv) Potentialdifferenceapplied acrosstheconductor

1

3 1
The temperature (T) dependence of resistivity of materials
Aand material B is represented by fig(i) and fig (ii)
respectively.IdentifymaterialAandmaterial B.

(i) material Aiscopperandmaterial Bisgermanium
(ii) material Aisgermaniumandmaterial Biscopper
(iii) material Aisnichrome and materialBis germanium
material Aiscopperandmaterial Bisnichrome
4 Wheatstonebridgecannot beused formeasuring ofvery 1
………………….resistances
(i) high
(ii) low
(iii) lowor high
(iv) mediumvalue

5 If the magnetizing field on a ferromagnetic 1
materialisincreased,its permeability
(i) decreases
(ii) increases
(iii) remainsunchanged
(iv) firstdecreasesandthen increases
6 An iron cored coil is connected in series with an electric 1
bulbwith an AC source as shown in figure. When iron piece
istakenout ofthecoil,thebrightnessof thebulbwill

(i) decrease
(ii) increase
(iii) remainunaffected
(iv) fluctuate

2

7 A ray of light passing from air through an equilateral 1
glassprism undergoes minimum deviation when the angle
ofincidence is ¾ of the angle of prism. speed of light in
theprismis.
i) c
ii) c/2
iii) c/4
(iv) none
8 Which of the following statement is NOT true about 1
thepropertiesof electromagneticwaves?
(I)These waves do not require any material medium for
theirpropagation
(ii) Both electric and magnetic field vectors attain the maxima
andminimaat thesametime
(iii) The energy in electromagnetic wave is divided equally
betweenelectricand magneticfields

iv) Both electricand magnetic field vectors
areparalleltoeachother
9 In two positions convex lens produces magnified image of 1
givenobject.Thepositions are
i) At f,at2f
ii) Betweenf and2f,between opticalcenter andf
iii) Beyond2f, betweenc and f
iv) At2f,betweenopticalcentreandf
10 If Young’s double slit experiment is immersed in water, 1
thenfringewidth
(i) decreases
(ii) increases(iii
)remainsame
(iv)none
11 The work function for a metal surface is 4.14 eV. The 1
thresholdwavelengthfor thismetal surfaceis:
(i) 4125Å
(ii)2062.5Å
(iii) 3000Å
(iv) 6000Å

3

12 The radius of the inner most electron orbit of a hydrogen 1
atom is5.3×10–11m.Theradiusof then=3orbitis
i) 1.01x1–10m
ii) 1.59X10-1m
iii) 2.12x10-10 m
iv) 4.77X10-10m
13 Whichof thefollowing statementsaboutnuclear forces is nottrue? 1
(i) The nuclear force between two nucleons falls rapidly to zero
astheirdistanceis more than afewfemtometers.
(ii) Thenuclearforceismuchweakerthan theCoulomb force.
(iii) The force is attractive for distances larger than 0.8 fm
andrepulsiveif theyareseparated bydistancesless than 0.8
fm.
(iv) Then nuclear force between neutron-neutron, proton-
neutron andproton-protonis approximatelythesame.
14 Poweroflens is 10 diopters,which of following is correct 1
(i) Convexlensoffocallength10metre
(ii) Convex lens of focallength10 cm
(iii) Concavelensoffocallength10metre
(iv) Concave lens of focallength10cm
15-18 Twostatementsaregiven-onelabeled 1
Assertion(A)and the other labeled Reason(R). Select the
correct answer tothesequestions fromthecodes (a),(b),(c)
and(d)asgivenbelow.
a) BothAand Rare trueandRisthecorrectexplanation of A
b) Both A and R are true and R is NOT the correct explanation ofA
c) A is true but R is false
d) A is false and R is also false

15. Assertion : A p-type semiconductors is a positive type crystal.
Reason : A p- type semiconductor is an uncharged crystal.

4

16. ASSERTION(A):
Theelectrical conductivityof asemiconductorincreasesondoping.
REASON (R) :
Dopingalways increases the number of electrons in
thesemiconductor.

17 Twostatementsaregiven-onelabeled 1
Assertion (A) and the other labelled Reason (R). Select
thecorrectanswer to these questions fromthecodes (a),(b),(c)and
(d)asgivenbelow.
a) Both Aand Raretrueand Risthe correctexplanation ofA
b) Both Aand Raretrueand Ris NOTthe correctexplanationofA
c) Aistruebut Ris false
d) Aisfalseand Ris also false

ASSERTION:
In an interference pattern observed in Young's double
slitexperiment, if the separation (d) between coherent sources as
well asthedistance
(D) of the screen from the coherent sources both are reduced
to1/3rd.,thennewfringewidth remainsthe same.
REASON:
Fringewidthisproportionalto(d/D).
18 Two statements are given-one labeled Assertion (A) and 1
theother labelled Reason (R). Select the correct answer to
thesequestions from the codes (a), (b), (c) and (d) as given
below.a)BothAandRare true andRisthecorrect explanationof A
b) Both Aand RaretrueandRisNOTthecorrect explanation ofA
c) Aistruebut Ris false
d) Ais falseand Risalso false
Assertion(A):
The photoelectrons produced by a mono chromatic light
beamincidenton ametalsurfacehaveaspreadintheirkineticenergies.
Reason(R):
The energy of electrons emitted from inside the metal surface,
islostin collision withthe other atoms inthemetal.

5

SECTIONB

19 Electromagneticwaveswith wavelength 2
(i) λ1 is suitable for radar systems used in air
craftnavigation.
(ii) λ2isusedtokillgermsinwaterpurifiers.
Identify and name the part of the electromagnetic spectrum
towhichthese radiations belong.

20 A uniform magnetic field gets modified as shown in 2
figurewhentwospecimensAandBareplaced init.

Identifythe specimenAandB.

21 State biot savarts 2
law.?OR
Stateamperescircuitallaw
22 Stateworkingprincipleofmovingcoilgalvanometer? 2

23 A proton, deutron and alpha particle enter with same 2
momentumperpendicular to same magnetic field. What is The
ratio of radii ofproton,deutron and alphaparticle
24 A narrow slit is illuminated by a parallel beam of 2
monochromaticlight of wavelength λ equal to 6000 Å, separation
between the slitis2 cm. whatis the angular width of the central
maxima.
25. Define distance of closest approach in Rutherford alpha 2
scatteringexperiment. Writemathematical formula.
OR
Explain Rutherford alpha scattering experiment.

6

SECTIONC
26. Two large, thin metal plates are parallel and close to each other.On 3
their inner faces, the plates have surface charge densities ofopposite
signs and of magnitude17.7×10-22C/m2. What is
electricfieldintensityE:

(a) intheouter regionofthefirstplate,and
(b) betweentheplates?

27 Statelawsofphotoelectric effect? 3

28 Explaintheprocessesofnuclearfissionandnuclearfusionbyusingtheplotofbin 3
dingenergypernucleon(BE/A)versusthemassnumberA.

29 An a.c. source generating a voltage ε = E0sin ωt is connected to 3
acapacitor of capacitance C .Find the expression for the current
Iflowing through it. Plot a graph of ε and I versus ωt to show
thatthecurrent isahead ofthevoltage byπ/2.
OR
An ac voltage V = V0sin ωt is applied across a pure inductor
ofinductanceL. Find an expression for the current i, flowing in
thecircuit and show mathematically that the current flowing through
itlags behind the applied voltage by a phase angle ofπ/2..Also
drawgraphsofVandIversus ωtforthecircuit.

30. WriteBohr'spostulatesforthehydrogenatommodel.

SECTIOND

31 What is p n junction diode. Explain the process involved 5
information of p n junction diode with the help of
suitablediagram
OR
Explain principle and working of p n junction diode in
fullwave rectifier?

7

32 (a) Explain the term drift velocity of electrons in a 5
conductor.Hence obtain the expression for the current
through aconductorin terms ofdrift velocity.

(b) Twocellsofemfs E1 andE2 andinternalresistances
𝑟1and𝑟2respectivelyareconnectedinparallel asshown
inthefigure.
Deducetheexpression forthe
(i) Equivalentemfof thecombination
(ii) equivalentinternalresistanceofthecombination
(iii) potentialdifferencebetweenthe pointsAandB.

OR

(a) State the two Kirchhoff’s rules used in
thenanalysisofelectriccircuitsandexplainthem
.
(b) Derivethe equationofthebalanced stateina
WheatstonebridgeusingKirchhoff’slaws.
33 a) Prove prism formula 5
b) ArayPQisincidentnormallyonthefaceAB ofa

8

triangularprismofrefractingangle600asshowninfigure.The
prism is made of a transparent material ofrefractive
index2/√3. Trace the path of the ray as it passesthrough
the prism. Calculate the angle of emergence
andtheangleofdeviation.

OR
(i) A ray of light incident on face AB of an
equilateralglass prism, shows minimum deviation of
30°.Calculatethe speed oflight through theprism.
(ii)FindtheangleofincidenceatfaceABsothattheEmerg
entraygrazesalong thefaceAC.

SECTIONE
34 CaseStudy: 4
Readthefollowing paragraphandanswerthequestions.
Smallest charge that can exist in nature is the charge of
anelectron. During friction it is only the transfer of electron which
makesthe body charged. Hence net charge on any body is an integral
multipleofcharge of an electron(1.6x 10-19C)i.e.,q=±ne
where r=1,2,3,4….
Hence no body can have a charge represented as 1.8e, 2.7e, 2e/5,
etc.Recently, it has been discovered that elementary particles such
asprotonsor neutrons are elemental unitscalledquarks
I) Ifachargeonabodyis1nC,thenhowmanyelectronsarepresen
t onthebody?
II) Chargeis scalarorvector ?
III) Apolythenepiecerubbedwithwoolisfoundtohavea
negativechargeof3.2x10-
7
C.Calculatethenumberofelectronstransferred.
OR
What is charge?
9

35 Casestudy:ElectromagneticInduction. 4
Readthefollowing paragraphandanswerthequestions

When a current I flows through a coil, flux linked with it is φ =
LI,whereLis a constant known as selfinductanceof the coil.

Any charge in current sets up an induced emf in the coil. Thus,
selfinductance of a coil is the induced emf set up in it when the
currentpassingthroughitchangesattheunitrate.Itisameasureoftheoppositi
on to the growth or the decay of current flowing through thecoil. Also,
value of self inductance depends on the number of turns inthe solenoid,
its area of cross-section and the permeability of its corematerial.
I) I) What is self inductance ?
II) II) State the factors on which self inductance of a long solenoid
depends?
III) What is theinducedemfinacoilof10henryinductanceinwhich
currentvaries from9 Ato 4 AIn 0.2 second
OR
What is Lenz’s law ?

10