1
SAMPLE QUESTION PAPER - 1
FOR CLASS XII - PHYSICS
BLUE PRINT
SL. No
1
2
3
4
5
6
7
8
9
10
TOTAL
UNIT
Electrostatics
Current Electricity
Magnetic Effect of Current and
Magnetism
Electromagnetic Induction and
Alternating Currents
Electromagnetic Waves
Optics
Dual Nature of Matter
Atoms and Nuclei.
Electronic Devices
Communication Systems
VSA
(1 Mark)
1(1)
-
SA I
(2 Marks)
2(1)
SA II
(3 Marks)
3(1)
-
1(1)
2(1)
1(1)
1(1)
1(1)
1(1)
1(1)
1(1)
8(8)
4(2)
2(1)
2(1)
2(1)
2(1)
16(8)
VBQ
(4MA
RKS)
4(1)
LA
(5 Marks)
5(1)
TOTAL
8(3)
7(2)
-
5(1)
8(3)
3(1)
6(2)
3(1)
3(1)
6(2)
3(1)
27(9)
5(1)
15(3)
8(4)
3(2)
14(5)
4(2)
6(3)
7(3)
5(2)
70(29)
4(1)
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SAMPLE PAPER-I
PHYSICS FOR CLASS XII
General Instructions:
(a) All questions are compulsory
(b) There are 29 questions in total. Qns. 1 to 8 carry 1 mark each. Qns. 9 to 16 carry 2 marks each,
Qns. 17 to 25 carry 3 mark,Qns. 26 carry 4 mark and Qns. 27 to 29 carry 5 marks each.
(c) There is no overall choice. However, an internal choice has been provided in one question of 2
marks, one question of 3 marks and all three questions of 5 marks each. You have to attempt
only one of the given choices in such questions.
(d) Use of calculators is not permitted.
(e) You may use the following physical constants wherever necessary.
c = 3 x 108 ms-1
h = 6.6 x 10-34Js
e = 1.6 x 10-19C
µo = 4π x 10-7 TmA-1
1/4πεo = 9 x 109 N m2C-2
Avogadro number
NA = 6.023 x 1023 mol-1
Mass of the neutron = 1.675 x 10-27 kg
Boltzmann constant, k = 1.38 x 1023 J K-1
1. An uncharged insulated conductor A is brought near a charged insulated conductor B. What
happens to charge and potential of B?
2. There are two identical galvanometers. One is converted into an ammeter and the other into
milliammeter. Which of the shunts will be of larger resistance?
3. Two identical loops, one of copper and another of constantan are removed from a magnetic
field within the same time interval. In which loop will the induced current be greater?
4. What is the ratio of speed of infra-red rays and ultra-violet rays in vacuum?
5. In Young’s double slit experiment, one slit is covered. What will be the effect?
6. On what factor does the energy carried by a photon of light depend?
7. Two nuclei have mass numbers in the ratio 1:8. What is the ratio of their nuclear radii?
8. In the following diagrams, which of the diodes are forward biased and which
are reverse biased?
9 In a metre bridge, the null point is found at a distance of 33.7 cm from A. If now
S, the null point occurs at
51.9 cm. Determine the values ofR and S.
3
10. A ray of light passes through an
equal to angle of emergence and the latter is equal to 3/4th of angle of prism. Calculate the angle
deviation.
11. A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a
current of 0.40 A. What is the magnitude of the magnetic field B at the centre
of the coil?
12.When the primary of a transformer is connected to the a.c. mains the current in it (a) is very
small if the secondary circuit is open but (b) increases when the secondary circuit is closed.
Explain.
13
through its centre and perpendicular to the disc. A uniform magnetic field of 0.2T acts
perpendicular to the disc.
(i) Calculate the potential difference developed between the axis of the disc and
the rim.
14 State any four properties of electromagnetic waves.
15. A radioactive isotope has a half-life of T years. How long will it take the activity
to reduce to a) 3.125%, b) 1% of its original value?
16. A modulating signal is a square wave, as shown in Figure .The carrier wave is
given by c(t
t) volts.
(i) Sketch the amplitude modulated waveform
(ii) What is the modulation index?
17. Define Electric flux . What is its S.I. Unit?
A student is asked to calculate the ratio of electric flux through the surfaces of
spheres S1 and S2 with charges placed inside, as shown in the figure. He gets
the answer as 4 : 1. Check the correctness of the answer by actually calculating the electric
flux ratio through the two surfaces and state whether his answer is correct or incorrect.
4
18. A series LCR circuit connected to a variable frequency 230 V source.
L = 5.0 H, C
R
(a) Determine the source frequency which drives the circuit in Resonance.
(b) Obtain the impedance of the circuit
(c) and the amplitude of current
at the resonating frequency.
19. Calculate the de-brogrlie wavelength of (i) an electron moving with a speed of
1/100 of speed of light in vacuum (ii) a ball of radius of 5mm and mass 0.03
kg moving with a speed of 100m/s . Hence show that the wave nature of matter
is important at the atomic level but is not really relevant at the macroscopic level.
20. Derive an expression for the total energy of electron in the nth orbit.
21. With the help of circuit diagram explain the working of a transistor as a switch.
22. Distinguish between metals, insulators and semiconductors on the basis of energy
band diagrams.
OR
With the help of circuit diagram explain the working of a p-n junction diode as a
full wave rectifier . Show the input and output wave forms.
23. A microwave telephone link operating at the central frequency of 10GHz has
been established.
If 2% of this available for microwave communication channel , then how many
telephone channels can be simultaneously granted if each telephone is allotted a
bandwidth of 8KHz.
24. Which of the following can be polarized : (i) X-rays and (ii) Sound waves. Give
reasons. Two polaroids are used to study polarization , one of them is kept fixed
and other is initially kept with its axis parallel to the polarizer axis . The analyzer
is then rotated through angles of 45,90 and 180 degrees in turn. How would the
intensity of light coming out of the analyzer be affected for these angles of
rotation, as compared to the initial intensity and why?
25. Show graphically the intensity distribution of a single slit diffraction pattern.
State with reason how would the linear width of central maximum change if (i)
monochromatic yellow light is replaced with red light (ii) distance between the
slit and screen is increased.
26.Two persons are standing under a tree and another person near them is inside a car. They were
arguing about going out for a movie or to the beach, when, a lightning struck the tree with some force.
The person inside the car notices his friends standing under the tree are affected by lightning; he
comes out and takes them to the nearby hospital.
a) Why the person in the car was not affected by lightning? What quality do you find in the
person inside the car?
b) Explain the process that takes place during lightning.
27 With the help of circuit diagram explain in brief the use of potentiometer for
5
comparison of emf of two cells.
A 10 m long wire of uniform crossboard. The wire is connected in series with a battery of 5V along with an external
E is balanced at 600 cm of this wire,
calculate (i) the potential gradient of wire, (ii) value of unknown e.m.f.
OR
State two kirchoff’s laws.
internal resistances of the cells are negligible.
28. How will a dia ,para , and a ferro magnetic material behave when kept in a non-uniform
external magnetic field . Give two examples of each of these materials . Name two main
charactrestics of a ferro magnetic material which help us to decide its suitability for making (i)
a permanent magnet (ii) an electro magnet. Which of these two characteristics should have
high or low values for each of these two types of magnets.
OR
With the help of labeled diagram explain the priniciple and construction of moving coil
galvanometer . Explain (i) importance of radial magnetic field. (ii) role of phosphor bronze
strip.
29 Write two conditions necessary for total internal reflection to take place.
A small bulb is placed at the bottom of a tank containing water to a depth of
80cm. What is the area of the surface of water through which light from the bulb
can emerge out. Refractive index of water is 1.33
OR
Draw a labeled diagram to show the image formation in an astronomical
telescope for normal adjustment position.
Two convex lenses of same focal length but aperture 5cm and 10cm are used as
objective lenses in two astronomical telescopes.
(i) What will be the ratio of their resolving power .
(ii) Compare the intensity of images formed in two cases.
***************************************
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SAMPLE PAPER-I
PHYSICS FOR CLASS XII
MARKING SCHEME
Q.No
1
No change in the Charge , potential decreases
½,1/2
Total
Marks
1
2
3
4
5
6
7
8
9
Milliammeter
Copper
1:1
Diffraction
Frequency
1:2
(i)forward (ii) reverse
a) due to electrostatic shielding the person in the car
was not affected (electric field inside the metallic body
is zero); helping others; taking a quick decision as to
what is to be done, in case, he is unaware or unable to
do on his own.
B) correct Reason
1
1
1
1
1
1
½,1/2
1 +1
1
1
1
1
1
1
1
2
10
Formula
used,
correct
answer
(R=6.86ohms
&S=13.5ohms)with units
i+e=A+d , d=30
B = 0NI/ 2r , 2.5 X 10-3T
When the secondary is open power output is zero, less
current flows in primary , when the secondary is closed
power out put is there , more current flows
Emf developed E = Br2/2 ,emf= 0.0618V,I=0.0309A
Any four properties
1+1
2
1+1
1+1
1+1
2
2
2
1+1
4x½
2
2
(a)A/A0=( ½)nn =5 (b)t=5T, N=N0e-t t=6.65T
Sketch, mod. Index = 0.5
 = q/01 : 2 = 1 : 1 ; his answer is incorrect
(a) = 1/2 LC  = 7.95Hz ,(b)Z = R=40,I0=V0/Z
I0=8.13A
=h/mve= 2.43 Ao ; ball =2.2 X 10-34m;
Derivation of En= - me4/802n2h2
Circuit diagram; working of transistor as switch
Energy band diagram of metals,semiconductors and
insulators
Circuit diagram, working of full wave rectifier ,wave
forms
No. of channels = Band width of the Channel/Bandwith
of signal, n= 25 X 105
X-rays, em waves are transverse hence can be polarized,
based on malus law I = I0 cos2
The intensity is ¼ , 0, ½ of initial intensity
1+1
1 +1
1+1+1
1+2
2
2
3
3
1+1+1
3
1+2
1+1+1
3
3
3
3
1+1+1
3
1+2
3
1+1+1
3
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Value points
Marks
7
26
27
28
29
Graph, width of central max= D/d, red has more wave
length compared to yellow, (i)width increases
(ii)increases
Circuit diagram, explanation, I = V/R ,I=0.01A, V/l=
0.02V/m ,E=0.12V
Kirchoff ‘s laws , correct answer
Dia ,para ,ferro magnetic properties , More coercivity and
more retentitivity for permanent magnet and less
coercivity and less retentivity for temporary magnet
Diagram, principle, working, to have linear scale , to
increase the current sensitivity k should be more
Two conditions ; sin  = 3/4tan=3/7 and r=3h/7
A=2.58sq.m
Labeled diagram, R.P=D/1.22R.P1: R.P2= 1:2
Intensity is proportional to diameter I1:I2=1 : 2
1+1+1
3
1+1+3
5
2+3
3+2
5
5
3+2
5
2+3
5
2+3
5