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SAMPLE QUESTION PAPER
.· CSOLVEDJ
••
Time Allowed : 3 Hours]
General Instructions : See CBSE Sample Question Paper _ [Maximum Marks : 70
2025

SECTION A
Q.t. Electric charges are distributed within a small volume. The electric flux through a spherical
surface of radius 0.2 m around the said volume is 50 V-m. Calculate the electric flux over
the surface of a concentric sphere of radius 0.5 m. ·
(a) 50 V-m (b) 312.5 V-m (c) 125 V-m (d) 20 V-m
Q.2. Two electric bulbs rated 100 W, 220 V and 40 W, 220 V respectively are joined in series
across a supply voltage of 220 V. Electric current passing through them is in the ratio
(a) 5 : 2 (b) 2 : 5 (c) 25 : 4 (d) 1 : 1
Q.3. Choose the correct statement out of the following :
(a) Resistivity of a wire depends on its material as well as dimensions.
(b) Resistance · of silicon increases with increase in temperature but that of copper
decreases with increase 'i n temperature.
(c) SI unit of electrical conductivity is S m-1.
(d) Ohm's law is a universal law.
Q•4. Un d er the influence o f a uniform magnetic field ' a charged particle moves
. with constant
speed v in a circle of radius r. The time period of revolution of the particle
•
(a) depends on v and not on r. · (b) depends on b randh not donr v.
(d) depends on ot van ·
(c) is independent of both v and r. h from 2 A to 4 A in 0.05 sis
Q.5. The average emf induced in a coil in which the current c anges
8 V. Self-inductance of the coil is
(d) 0.8 H
(a) 0.1 H - (b) 0.2 H . · (c~ ?.4~
Q6 . ac circmt 1s given as
·· The Q-factor of a resonant LCR senes R

· (a) Q == ,.lJ[c (b)

fc
Q = -1 C (c) Q = R {"[
VC (d) Q = JLC
R R ti ?
. of the following are least energe c .
Q.7. In the electromagnetic spectrum which c Infrared rays (d) Radio waves
(a) X-rays (b) Ultraviolet rays ()

SA~PLE 167
QUESTION PAPER - 6
 Q.8. If the 8th brig ht ban d of wav elen gth A.1 coin cide s wit h 9 th brig
ht ban ~ of wav elen gth ½ in
a You ng's dou ble- slit exp erim ent the n pos
sibl e wav elen gth s of two ligh ts are
(a) 11. =450 run, 11. =400 run
1 2 (b) 11.1 = 400 run , A-2 =450 run
(c) 11. =425 run, 11. =400 run
1 2 (d) 11.1 =400 run , A-2 =42~ run
Q.9. Tw o thin lens es of focal leng ths f and Ji are in con
1 tact and coaxial. The pow er of the
com bin atio n is

(a) fK
Vh (b) fK
Vli
Q.10. Tw o coh eren t ligh t bea ms of inte
(c) ii - h
hh
(d) \;l2
nsit ies I and 4I are sup erp ose d. The
min imu m pos sibl e inte nsit ies in the resu max imu m and
ltin g bea m are
(a) SI and 3I · (b) SI and I (c) 9I and I (d) 9I and 3I
Q.11. The rad ius of the inn erm ost elec
tron orb it of a hyd rog en ato m is 5.3 x 10-11
of the n = 3 orb it is m. The radius
(a) 1.01 x 10-10 m (b) 1.59 x 10-10 m
(c) 2.12 x 10-10 m (d) 4.77 x 10-10 m
Q.12. Wh ich of the following stat eme nt
is true for the nuc lear force bet wee n the
a nuc leu s? nuc leon s inside
(a)° Nuc lear force follows inv erse squ are law
.
(b) Nuc lear force is a cen tral force.
(c) The nuc lear force is mu ch wea ker tha
n cou lom bian _force.
(d) The nuc lear force is attr acti ve in nat
ure for dist anc es larg er tha n 0.8 £m but
in nat ure for dist anc es less tha n 0.8 fm. repulsive
For que stio ns 13 to 16, two statements
are giv en - one lab elle d Ass erti on (A)
lab elle d Rea son (R). Sel ect the correct and other
ans wer to the se que stio ns from the opt
giv en bel ow. ions as
(a) Bot h Ass erti on (A) and Rea son (R)
are true and Rea son (R) is cor rect explana
Ass erti on (A). tion of
(b) Bot h Ass erti on (A) and Rea son
(R) are true , but · Rea son (R) is not
exp lana tion of Ass erti on (A). the correct
'
(c) Ass erti on (A) is true , but Rea son (R)
is false.
(d) Bot h Ass erti on (A) and Rea son (R)
are false.
Q.13. Ass erti on (A) : Ma gne tic sus cep
tibi lity of par ama gne tic and fero mag neti
c substances is
pos itiv e but neg ativ e for diam agn etic sub
stan ces .
Rea son (R) : Alu min ium is a diam agn etic mat
eria l but soft iron is para mag neti c in
natu re.
Q.14. Ass erti on (A) : Dis plac eme nt cur
ren t is the cur ren t cau sed by disp lace men
t of electrons
in a con duc tor wh en a var yin g electric fiel
d is app lied acro ss its ends.
Rea son (R) Electromagnetic wav es wer e exp erim enta
lly dete cted by Maxwell and
theo ry of thes e wav es was giv en by Her
tz and Ma rcon i. ,
Q.15. Ass erti on (A) : The pho toel ectr
ons pro duc ed by a mon och rom atic ligh
t bea m incident
on a met al surf ace hav e a spr ead in the ir
kine tic ene rgie s.
Rea son (R) The ene rgy of elec tron s emi tted from insi
de the met al surface, is lost in
collision wit h the oth er atom s in the met
al.

U-LIKE PHYSICS-XII
 Assertion (A) The electrical ·
conductivity o f a semiconductor ·
increases ·
on doping.
6
Q1· .
· Reason (R) Doping always increases the number of electrons in the semiconductor.

SECTION B
Q.17, Electrical resistance of a given co uctor is 5.0 n at O °C
nd and 7.0 n at 200 °C. Calculate the
average value of temperature coefficient of resistance (a) of material of given conductor for
this temperature range. _
Q.1S, A uniform magnetic field gets modified as shown in figure when two specimens A and B
are placed in it.
------

(a) (b)

(i) Identify the specimen A and B.

(il) · How is the magnetic susceptibility of specimen A different from that of specimen
B?
s. The electron in each atom is in an excited
Q.19. (A) Consider two different hydrogen atom_
state. Is it possible for the electrons to have different energies but same orbital angular
momentum according to the Bohr model? Justify your answer.
Or
(B) Find the ratio of energies of photons produced due to transition of an electron of
hydrogen atom from i~s
(1) second permitted energy level to the first level, and
(ii) the highest permitted energy level to the first permitted level.
Q.20. Find the net current flowing ·through the circuit arrangement shown here. It is given that
both diodes are ideal didoes.

1 k!l
£ = 6.0 V
Q,2l, A plane electromagnetic wave has frequency of 2.0 ~ 10 _ Hz and ~ts average en~rgy
12

density is 1.02 x 10-B J m-3 in free space. Find the amplitude of magnetic field of the given
em.wave.
SECTION C
Q.22. (a) State Gauss law in electrostatics and give its mathematical expression.
(b) Obtain an expression for electric field inte~ity at a point due to an infinitely long
charged wire.

SAIAPl.£ QUESTION PAPER - 6

 Q.23. (a) Define interna l resistan ce of a cell.
(b) Name any three factors on which interna l resistan ce of a cell depend.
(c) Under which conditi on can we draw a maxim um curren t from a cell ? What is
the
value of this curren t ?
Q.24. (A) (a) Define inducti ve reactan ce and give its SI unit.
(b) A 0.7 H inducto r is connec ted across a 220 V - 50 Hz A.C. source. Find
the current
flowing throug h the conduc t~r.
Or
(B) (a) Define capacit ive reactan ce of a capacit or. On which factors does it
depend?
(b) A capacit or of 35 µFis connec ted across a 220 V - 50 Hz A.C. supply. Find
the
curren t passing throug h the capacit or.
Q.25. The magnet ic field throug h a circula r loop of wire, 12 cm in radius and 8.5
·n resistance,
change s with time as shown in the figure. The magne tic field is perpen dicular to the plane
of the loop. Calcula te the curren t induce d in the loop and plot a graph showing induced
curr:ent as a functio n of time.
B(T)

I I I
2 ----~ ----~ ----~
I I I
I I I
I I I
.1 ----~•I----~
I
I I
I I

0 2 4 6 t(s)
Q.26. (i) Draw a neat labelle d ray diagram of a compo und micros cope. Explain
briefly its
workin g. .
(ii) Why must both the objective and the eyepiec e of a compo und microscope
have short
focal lengths ?
Q.27. Show that the superp osition of the waves origina ting from two cohere nt
sources s1 and
s2 having displac ements y1 = a cos rot and y = a cos (wt+ <I>) at a point produc e a resultant
2

intensi ty IR = 4a2 cos2 ( ~ ) • Hence, write the conditi ons for the appearance of dark and
bright fringes.
Q.28. (A) (a) How is the radius of a nucleu s related to its mass numbe r?
(b) A heavy nucleu s X of mass numbe r 240 and bindin g energy per nucleon 7.6
MeV is
split into two fragme nts Y and Z of mass numbe rs 11 0 and 130. The binding energ}'
of nucleo ns in Y and Z is 8.5 MeV per nucleo n. Calcula te the energy Q released per
fission in MeV.
Or
(B) (a) Draw a plot of potenti al energy of a pair of nucleo ns as a functio n of
their separa·
tion.
(b) Write any four import ant feature s of nuclea r forces.

U-UKE pffYSICS""Xll
 SECTION D
Case Study Based Questions
Q.29. Read the following paragraph and answer the questions that follow :
Metals have free electrons which move randomly inside that metal and behave as an electron
gas. However, these free electrons cannot normally escape out of the metal surface. Hertz
observed that ultraviole t light falling on a 1?'.letal surface some how facilitated the escape
of free electrons. This phenomen on is known as photoelect ric emission. The phenomen on
was studied in detail by Lenard and Hallwachs and was successful ly explained by Einstein
on the basis of photon nature of radiation.
(i) The energy of a photon of waveleng th '). , is
he (d) A,
(a) h')... (b) he')... (e) . 'A, he
(ii) The mass of a photo electron is
31 31
(a) 9.1 x 10-27 kg (b) 1.66 x 10-27 kg (e) 9.1 x 10- kg (d) 1.66 x 10- kg
(iiz) When light falls on a metal surface and causes emission of photoelec trons, the
maximum kinetic energy of these photoelec trons depends upon
(a) frequency of incident light. (b) intensity of incident light.
(e) speed of incident light. (d) time for which light falls on the metal.
(iv) (A) The threshold frequency for a certain photosens itive metal is .v0• When it
is illuminate d by light of frequency v = 2vo, the maximum velocity of the
photoelec trons is v 0 • What will be the maximum velocity of the photoelec trons
when the same metal is illuminate d by light of frequency v' = Sv0 ?
(a) ✓2. v0 (b) ✓Sv0 (e) 4v0 (d) 2v 0
Or
(B) Ultraviole t radiation of 6.2 eV falls on an aluminium surface (work function 4.2 eV).
The kinetic energy in joules of the fastest electron emitted is
(a) 3.21 x 10- 21 J (b) 1.6 x 10-17 J (e) 6.0 x 10-9 J (d) 3.2 x 10-19 J

Q.30. Read the following paragraph and answer the questions that follow :
Semicond uctors are those substance s whose resistivity or conductiv ity is intermedi ate
to metals and insulators . Electrical conductiv ity of naturally occurring semicond uctor
materials depends on its temperatu re but at room temperatu re value of conductiv ity is
very low. To enhance the conductiv ity of a semicondu ctor we make use of doping process
in which a controlled quantity of suitable impurity is injected into the given semicondu ctor.
(i) Choose the only semicondu ctor out of the following :
(a) platinum (b) silicon (e) tin (d) gallium
(iz) To obtain a p-type semicond uctor the dopant used is
(a) aluminium (b) phosphoro us
(c) nitrogen (d) sulphur
(iiz) When the electrical conductiv ity of a semicond uctor is due to the breaking of its
covalent bonds, the semicond uctor is.said to be
(a) donor (b) acceptor (c) intrinsic (d) extrinsic

SAMPLE QUESTION PAPER - 6 171

◊
 (iv) (A)Select the correct statement out of the following:
(a)n-type silicon is negatively charged and p-type silicon is positively charged.
(b)n-type silicon is positively charged and p-type silicon is negatively charged.
(c)Both n-type and p-type silicons are electrically neutral.
(d)At low temperature n-type silicon is negatively charged but at high temperature it
becomes positively charged. ·
Or
(B) A hole in a p-type semiconductor is
(a) an excess electron. · · (b) a donor level.
(c) a missing electron. _ (d) a positive electron.
SECTION E
Q.31. (A) (a) Draw the graph showing intensity distribution of fringes with phase angle due
to diffraction through a single-slit. What is the width of the central maximum in
comparison to that of a secondary maximum ? p A
(b) A ray PQ is incident normally on the face AB of a trian-
gular prism of refracting angle 60° as shown in figure.
The prism is made of a transparent material of refractive
2 . '
index r,; . Trace the path of the ray as it passes through
v3 ·
the prism. _Calculate the angle of emergence and the B C
angle of deviation.
Or
(B) (a) Write two points of difference between an interference A
pattern and a diffraction pattern. ·
(b) (1) A ray of light incident on face AB of an equilateral glass
· prism, shows minimum deviation of 30°. Calculate the
speed of light through the prism.
(ir) Find the angle of incidence at face AB so that the emergent
· ray grazes along the face AC. = - . B C
Q.32. (A) (a) Derive an expression for electrostatic potential energy stored in a charged
. capacitor. _· · - _ •
(b) A regular hexagon of side 0.1 m has a charge 2 x 10-S C at each of its vertices. Cal·
cu.late the electric potential at the centre of the_hexagon. _
. . . -· . . o, . .· . .. .
(B) (a) ·AchargeQisdistributedoverthesurfacesoftwoconcentrichollowspheresofradilr~d
R(R >> r), such that their surface charge densities are equal. Derive the expression
for the potential at the common centre. +
02
(b) Draw 3 equipotential surfaces corresponding to a field
that uniformly increases in magnitude but remains
constant along Z-direction. How are these surfaces +

different from that of a constant electric field along

Z-direction ?
♦

.. nlftr..4:-Xd
U-UKE I'll J,J.-
Q.33. (A) (a) Deri ve an expr essio n for the force actin g on
a y
curre nt carry ing cond ucto r place d in a unifo rm p
mag netic field. Nam e the rule whic h gives the
direc tion of the force. Writ e the cond ition for
whic h this force will have (i) max imum (ii) ~1__ _ _ _~x
0 ._..,..
.,_..,.
mini mum valu e.
➔ "
(b) An elem ent d l = Ax i is place d at the origi n as
show n in figur e and carri es a curre nt I = 2 A.
Find out the magn etic field at a poin t Pon the
y-axis at a dista nce of 1.0 m due to the elem ent
ax= 1 cm. Give the direction of the field produced.
Or
Also give an expr essio n
(B) (a) A curre nt loop is cons idere d a magn etic dipo le. Explain.
for its dipo le mom ent.
(b) Two long strai ght paral lel cond uctor s carry ing curre nts 11
and 12 alon g the same
the force of
direc tion are sepa rated by a dista nce 'd'. How does one expl ain
attra ction betw een them ?
is plac ed just
If a third cond ucto r carry ing a curre nt / 3 in the oppo site direc tio~
g on the third
in the midd le of these cond uctor s, find the resul tant force actin
cond uctor .