HBSE Class 12 Question Paper 2020 Physics

CLASS : 12th (Sr. Secondary) Code No. 4928
Series : SS-M/2020

Roll No. SET : A

HkkSfrd foKku
PHYSICS
[ Hindi and English Medium ]
ACADEMIC/OPEN
(Only for Fresh/Re-appear Candidates)

Time allowed : 3 hours ] [ Maximum Marks : 70
• Ñi;k tk¡p dj ysa fd bl iz'u&i= esa eqfnzr i`"B 16 rFkk
iz'u 21 gSaA
Please make sure that the printed pages in this
question paper are 16 in number and it contains
21 questions.
• iz'u&i= esa nkfgus gkFk dh vksj fn;s x;s dksM uEcj rFkk lsV dks
Nk= mÙkj&iqfLrdk ds eq[;&i`"B ij fy[ksaA
The Code No. and Set on the right side of the
question paper should be written by the candidate
on the front page of the answer-book.
• Ñi;k iz'u dk mÙkj fy[kuk 'kq: djus ls igys] iz'u dk Øekad
vo'; fy[ksaA
Before beginning to answer a question, its Serial
Number must be written.

4928/(Set : A) P. T. O.

(2) 4928/(Set : A)
• mÙkj&iqfLrdk ds chp esa [kkyh iUuk@iUus u NksMsa+A
Don’t leave blank page/pages in your answer-book.

• mÙkj&iqfLrdk ds vfrfjDr dksbZ vU; 'khV ugha feysxhA vr%
vko';drkuqlkj gh fy[ksa vkSj fy[kk mÙkj u dkVsaA
Except answer-book, no extra sheet will be given.
Write to the point and do not strike the written
answer.

• ijh{kkFkhZ viuk jksy ua0 iz'u&i= ij vo'; fy[ksaA
Candidates must write their Roll Number on the
question paper.

• d`i;k iz'uksa dk mÙkj nsus lss iwoZ ;g lqfuf'pr dj ysa fd iz'u&i=
iw.kZ o lgh gS] ijh{kk ds mijkUr bl lEcU/k esa dksbZ Hkh nkok
Lohdkj ugha fd;k tk;sxkA
Before answering the questions, ensure that you
have been supplied the correct and complete
question paper, no claim in this regard, will be
entertained after examination.

lkekU; funsZ'k %
(i) ç'u-i= esa dqy 21 ç'u gSaA

(ii) lHkh ç'u vfuok;Z gSaA

(iii) ç'u la[;k 1 esa 1-1 vadksa ds pkSng (i-xiv) oLrqfu"B ç'u
gSaA

4928/(Set : A)

(3) 4928/(Set : A)
(iv) ç'u la[;k 2 ls 11 rd vfry?kq mÙkjh; ç'u gSa rFkk çR;sd
ç'u 2 vadksa dk gSA
(v) ç'u la[;k 12 ls 18 rd y?kq mÙkjh; ç'u gSa rFkk çR;sd
ç'u 3 vadksa dk gSA
(vi) ç'u la[;k 19 ls 21 rd nh?kZ mÙkjh; ç'u gSa rFkk çR;sd
ç'u 5 vadksa dk gSA
(vii) ç'u-i= esa lexz :i ls dksbZ fodYi ugha gSA rFkkfi 5 vadksa
okys rhuksa ç'uksa esa vkUrfjd p;u çnku fd;k x;k gSA ,sls
ç'uksa esa ls vkidks fn, x, p;u esa ls dsoy ,d gh ç'u
djuk gSA
(viii)dSYD;qysVj ds mi;ksx dh vuqefr ugha gSA vko';d gksus ij]
y?kqx.kdh; lkjf.k;ksa dk ç;ksx fd;k tk ldrk gSA
(ix) tgk¡ vko';d gks vki fuEufyf[kr HkkSfrd fu;rkadksa ds ekuksa
dk mi;ksx dj ldrs gSa %
c = 3 × 10 8 m/s µ 0 = 4π × 10 −7 Tm A −1
1
h = 6.63 × 10 −34 JS = 9 × 10 9 Nm2C − 2
4π ∈0

e = 1.6 × 10 −19 C me = 9.1 × 10 −31 kg

General Instructions :
(i) There are 21 questions in all.
(ii) All questions are compulsory.

4928/(Set : A) P. T. O.

(4) 4928/(Set : A)
(iii) Question number 1 consists of fourteen (i-xiv)
objective type questions each of 1 mark.

(iv) Question Numbers 2 to 11 are very short
answer type questions and carry 2 marks
each.

(v) Question Numbers 12 to 18 are short answer
type questions and carry 3 marks each.

(vi) Question Numbers 19 to 21 are long answer
type questions and carry 5 marks each.

(vii) There is no overall choice. However, an
internal choice has been provided in all three
questions of 5 marks each. You have to
attempt only one of the given choices in such
questions.

(viii)Use of Calculators is not permitted, if
required you may use logarithmic tables.

(ix) You may use the following values of physical
constants whenever necessary :

c = 3 × 10 8 m/s µ 0 = 4π × 10 −7 Tm A −1
1
h = 6.63 × 10 −34 JS = 9 × 10 9 Nm2C − 2
4π ∈0

e = 1.6 × 10 −19 C me = 9.1 × 10 −31 kg

4928/(Set : A)

(5) 4928/(Set : A)
[ oLrqfu"B iz'u ]

[ Objective Type Questions ]

1. (i) fdlh v/kZpkyd dh izfrjks/kdrk dk SI ek=d fyf[k,A 1

Write SI unit of resistivity of a

semiconductor.

(ii) fdlh 'kq) /kkfjrh; ac ifjiFk ds 'kfDr xq.kkad dk eku

fdruk gksrk gS \ 1

What is the value of power factor of a purely

capacitive ac circuit ?

(iii) izdk'k rjaxksa dh izÑfr dks dkSu&lk izHkko Li"V djrk gS \

1

Which phenomenon illustrates the nature of

light waves ?

(iv) jsfM;ks,sfDVo /kkrq dh lfØ;rk dk SI ek=d D;k gS \ 1

What is SI unit of activity of radioactive

substance ?

4928/(Set : A) P. T. O.

(6) 4928/(Set : A)
(v) NOR xsV dk rdZ izrhd cukb,A 1

Draw logic symbol of NOR gate.

(vi) ,saVhuk }kjk fofdfjr 'kfDr rjaxnS?;Z ij dSls fuHkZj djrh
gS \ 1

How does the power radiated by an antenna
vary with wavelength ?

(vii) 10 V fo|qr~ okgd cy dh lapk;d cSVjh dk vkarfjd
izfrjks/k 0.2 Ω gSA cSVjh ls vf/kdre fdruh /kkjk yh tk
ldrh gS \ 1

What is the maximum current that can be
drawn from a storage battery of emf 10 V
and internal resistance 0.2 Ω ?

(viii),d /kukRed vkosf'kr d.k o ,d _.kkRed vkosf'kr d.k
ds chp vkd"kZ.k cy F gSA muds chp dh nwjh ,d pkSFkkbZ
djus ij bl cy dk eku D;k gksxk \ 1

The force of attraction between a positively
charged particle and a negatively charged
particle is F. When distance between them is
made one fourth, what will be the value of
this force ?

4928/(Set : A)

(7) 4928/(Set : A)
(ix) pqacdh; ¶yDl ?kuRo dk SI ek=d fyf[k,A 1

Write SI Unit of magnetic flux density.

(x) flfydkWu (Si) dks p-izdkj dk v/kZpkyd cukus esa dkSu&lk
vifeJd mi;qDr ugha gks ldrk \ 1

(A) In (B) Al

(C) B (D) P

Which dopant cannot be used to make
silicon (Si) a p-type semi-conductor ?

(A) In (B) Al

(C) B (D) P

(xi) gkbMªkstu ijek.kq dh vk;uu ÅtkZ gksrh gS % 1

(A) 13.6 J (B) 13.6 eV

(C) 1 eV (D) 10.2 eV

The ionization energy of hydrogen atom is :

(A) 13.6 J (B) 13.6 eV

(C) 1 eV (D) 10.2 eV

4928/(Set : A) P. T. O.

(8) 4928/(Set : A)
(xii)15 lseh Qksdl nwjh dk iryk mÙky ysal 15 lseh Qksdl
nwjh ds irys vory ysal ds laidZ esa j[kk gSA la;kstu dh
{kerk fdruh gS \ 1

(A) 0 D (B) ∞ D

(C) 3 D (D) 6 D

A thin convex lens of focal length 15 cm is
placed in contact with a thin concave lens of
focal length 15 cm. What is the power of the
combination ?

(A) 0 D (B) ∞ D

(C) 3 D (D) 6 D

(xiii)fuEu esa fdldh rjaxnS?;Z lcls de gS \ 1

(A) xkek fdj.kksa dh (B) X-fdj.kksa dh

(C) vojDr fdj.kksa dh (D) y?kq jsfM;ks rjaxksa dh

Which of the following has lowest wave-
length ?

(A) Gamma rays (B) X-rays

(C) Infrared rays (D) Short radio waves

4928/(Set : A)

(9) 4928/(Set : A)
(xiv)fdlh LFkku ds pqacdh; ;kE;ksÙkj esa i`Foh ds pqacdh; {ks=
dk {kSfrt vo;o 0.16 G rFkk ueu dks.k 60° gSA bl
LFkku ij i`Foh dk pqacdh; {ks= gS % 1

(A) 0.32 G (B) 0.36 G

(C) 0.18 G (D) 0.16 G

In the magnetic meridian at a certain
location, the horizontal component of earth's
magnetic field is 0.16 G and angle of dip is
60°. The earth's magnetic field at this
location is :

(A) 0.32 G (B) 0.36 G

(C) 0.18 G (D) 0.16 G

[ vfry?kq
vfry?kq mÙkjh; ç'u ]
[ Very Short Answer Type Questions ]

2. fo|qr~ {ks= js[kk,¡ D;k gksrh gSa \ fdlh fcanq vkos'k –Q ds fy,
bu js[kkvksa dks [khafp,A 2

What are electric field lines ? Draw these for a
point charge –Q.

4928/(Set : A) P. T. O.

( 10 ) 4928/(Set : A)
3. fo|qr~ {ks= E o fo|qr~ foHko V esa laca/k LFkkfir dhft,A 2

Derive relation between electric field E and
potential V at a point.

4. fn;s x;s fp= esa A o B fcUnqvksa ds chp rqY; izfrjks/k Kkr
dhft, % 2
4Ω 5Ω
9Ω
A B
5Ω 4Ω

9Ω

Calculate the equivalent resistance between the
points A and B in the given Figure.

4Ω 5Ω
9Ω
A B
5Ω 4Ω

9Ω

5. lalwpd D;k gksrk gS \ 2

What is demodulation ?

4928/(Set : A)

( 11 ) 4928/(Set : A)
6. 1.6 xzke inkFkZ ds lerqY; ÅtkZ dk eku igys twy o fQj
MeV esa Kkr dhft,A 2

Calculate the energy equivalent of 1.6 gram of a
substance first in Joules and then in MeV.

7. ;fn lhft+;e dk dk;Z&Qyu 2.14 eV gks] rks bldh nsgyh
vko`fÙk Kkr dhft,A 2

If the work function of Caesium is 2.14 eV then
find its threshold frequency.

8. foLFkkiu /kkjk dks ifjHkkf"kr djsa rFkk bldk xf.krh; :i fy[ksaA
2

Define Displacement current and write its
mathematical form.

9. ysat ds fu;e dks fyf[k,A 2

State Lenz's law.

10. 100 Ω izfrjks/k ds Js.khØe esa ,d 0.5 H izsj.k dh daqMyh dks
240 V, 50 Hz dh vkiwfrZ ls tksM+k x;k gSA ;fn ifjiFk esa
/kkjk Irms = 1.29 A gks] rks gj vo;o ds fljksa ds chp rms
oksYVrk dh x.kuk dhft,A 2

4928/(Set : A) P. T. O.

( 12 ) 4928/(Set : A)
A coil of inductance 0.5 H and a resistance of

100 Ω are connected to a 240 V 50 Hz ac supply

in series. If the rms current in the circuit is

Irms = 1.29 A, calculate the rms value of potential

drop across each element.

11. ck;ks&lkoVZ ds fu;e dk mi;ksx djds fdlh /kkjkokgh o`Ùkkdkj
ik'k ds dsanz ij paqcdh; {ks= ds fy, O;atd fudkfy,A 2

Using Biot-Savart's law derive an expression for

the magnetic field at the centre of a current

carrying circular loop.

[ y?kq mÙkjh; ç'u ]

[ Short Answer Type Questions ]

12. fdlh iw.kZrjax fn"Vdkjh dk ifjiFk vkjs[k cukdj blds fuxZr
oksYVrk ds rjax:i dks le>kb,A 3

Draw a circuit diagram of a full wave rectifier

and explain its output waveform.

4928/(Set : A)

( 13 ) 4928/(Set : A)
13. gkbMªkstu ijek.kq ds fy, ÅtkZ&Lrj vkjs[k cukb, rFkk blds
LisDVªe esa ykbZeSu rFkk ckej Jsf.k;ksa ds fy, laØe.kksa dks
n'kkZb,A 3

Draw the energy level diagram for hydrogen
atom and show the transitions for Lyman and
Balmer series in its spectrum.

14. izdk'k&fo|qr~ izHkko D;k gksrk gS \ izdk'k&fo|qr~ /kkjk ij foHko
ds izHkko dks le>kb,A 3

What is photoelectric effect ? Explain variation of
photoelectric current with applied potential.

15. ;ax ds f}f>jh iz;ksx esa dasnzh; nhIr fÝat ,oa prqFkZ nhIr fÝat ds
chp dh nwjh 1.2 lseh ekih xbZ gSA ;fn f>fj;ksa ds chp dh nwjh
0.28 feeh rFkk ijns dks 1.4 eh nwjh ij j[kk x;k gks] rks bl
iz;ksx esa mi;ksx fd;s x;s izdk'k dh rjaxnS?;Z Kkr dhft,A 3

In Young's double-slit experiment the distance
between the central bright fringe and the fourth
bright fringe is measured to be 1.2 cm.
Determine the wavelength of the light used if the
slits are separated by 0.28 mm and the screen is
placed 1.4 m away.

4928/(Set : A) P. T. O.

( 14 ) 4928/(Set : A)
16. fdlh Js.khc) LCR ifjiFk esa vuqukn dh rh{.krk dks
le>kb,A bl ifjiFk ds xq.koÙkk xq.kkad Q dks ifjHkkf"kr dj
blds fy, O;atd fyf[k,A 3

Explain sharpness of resonance in a series LCR
circuit. Define its quality factor Q and write
expression for it.

17. OghVLVksu lsrq dk ifjiFk vkjs[k cukb,A xSYosuksehVj esa 'kwU;
fo{ksi ds fy, larqyu izfrca/k fudkfy,A 3

Draw the circuit diagram of a Wheatstone
bridge. Derive its balance condition to give null
deflection in galvanometer.

18. oS|qr~ LFkSfrdh esa xkml ds fu;e dks fyf[k, o fl) dhft,A 3

State and prove Gauss's law in Electrostatics.

[ nh?kZ mÙkjh; ç'u ]

[ Long Answer Type Questions ]

19. fdlh [kxksyh; nwjchu esa izfrfcac cuus dk ukekafdr fdj.k
vkjs[k cukdj le>kb,A bldh vko/kZu {kerk ds fy, O;atd
fudkfy,A 5

Draw a labelled ray diagram showing image
formation in an astronomical telescope. Derive
expression for its magnifying power.

4928/(Set : A)

( 15 ) 4928/(Set : A)
vFkok
OR

fdlh la;qDr lw{en'khZ esa izfrfcac cuus dk ukekafdr fdj.k
vkjs[k cukdj le>kb,A bldh vko/kZu {kerk dks ifjHkkf"kr
djds blds fy, O;atd fyf[k,A 5

Draw a labelled ray diagram showing image
formation in a compound microscope. Define its
magnifying power and write expression for it.

20. fdlh VªkaftLVj dh mHk;fu"B mRltZd jpuk esa V-I
vfHkyk{kf.kd v/;;u ds fy, ifjiFk vkjs[k cukb,A blds
iz:ih fuxZr V-I vfHkyk{kf.kd oØksa dks [khapdj le>kb,A 5
Draw a Circuit diagram for studying V-I
characteristics for a transistor in common
emitter (CE) configuration. Draw and explain its
typical output V-I characteristics.

vFkok
OR

mHk;fu"B mRltZd VªkaftLVj izo/kZd dh dk;Zfof/k dks ifjiFk
vkjs[k cukdj le>kb,A 5

Explain the working of common emitter
transistor amplifier using circuit diagram.

4928/(Set : A) P. T. O.

( 16 ) 4928/(Set : A)
21. fdlh lkbDyksVªkWu dk O;oLFkk vkjs[k cukdj blds fl)kar o
dk;Zfof/k dk o.kZu dhft,A n'kkZb, fd blesa fdlh vk;u ds
ifjØe.k dk le; vk;u dh pky vFkok d{kk dh f=T;k ij
fuHkZj ugha djrkA 5

Explain the principle and working of a cyclotron
using its schematic sketch. Show that time of
revolution of an ion is independent of its speed
or radius of its orbit.

vFkok
OR

nks yacs lh/ks lekarj pkydksa ds chp yxus okys cy ds fy,
O;atd fudkfy, ftuesa fo|qr~ /kkjk ,d gh fn'kk esa cg jgh gksA
vr% ,d ,sfEi;j dks ifjHkkf"kr dhft,A 5

Derive an expression for the force between two
long straight parallel conductors carrying
current in same direction. Hence define one
Ampere.

S
4928/(Set : A)