Page 1
CBSE XII | PHYSICS
Board Paper – 2019
CBSE
Class XII Physics
Board Paper - 2019
Time: 3 hours Maximum Marks: 70
General Instructions:
(i) All questions are compulsory. There are 27 questions in all.
(ii) This question paper has four sections: Section A, Section B, Section C, and
Section D.
(iii) Section A contains five questions of one mark each, section B contains seven
questions of two marks each, section C contains twelve questions of three
marks each, section D contains three questions of five marks each.
(iv) There is no overall choice. However, an internal choice has been provided in
two question of one mark, two question of two marks, four questions of
three marks and three questions of five marks weightage. You have to
attempt only one of the choices in such questions.
(v) You may use the following values of physical constants wherever necessary:
c = 3 ? 10
8
m/s
h = 6.63 ? 10
-34
Js
e = 1.6 ? 10
-19
C
µ
0
= 4 p ? 10
-7
T mA
-l
?
0
= 8.854 ? 10
-12
C
2
N
-1
m
-2
0
1
4 ??
= 9 ? 10
9
N m
2
C
-2
Mass of electron
= 9.1 ? 10
-31
kg
Mass of neutron = 1.675 ? 10
-27
kg
Mass of proton = 1.673 ? 10
-27
kg
Avogadro’s number = 6.023 ? 10
23
per gram mole
Boltzmann constant = 1.38 ? 10
-23
J K
-1
Page 2
CBSE XII | PHYSICS
Board Paper – 2019
CBSE
Class XII Physics
Board Paper - 2019
Time: 3 hours Maximum Marks: 70
General Instructions:
(i) All questions are compulsory. There are 27 questions in all.
(ii) This question paper has four sections: Section A, Section B, Section C, and
Section D.
(iii) Section A contains five questions of one mark each, section B contains seven
questions of two marks each, section C contains twelve questions of three
marks each, section D contains three questions of five marks each.
(iv) There is no overall choice. However, an internal choice has been provided in
two question of one mark, two question of two marks, four questions of
three marks and three questions of five marks weightage. You have to
attempt only one of the choices in such questions.
(v) You may use the following values of physical constants wherever necessary:
c = 3 ? 10
8
m/s
h = 6.63 ? 10
-34
Js
e = 1.6 ? 10
-19
C
µ
0
= 4 p ? 10
-7
T mA
-l
?
0
= 8.854 ? 10
-12
C
2
N
-1
m
-2
0
1
4 ??
= 9 ? 10
9
N m
2
C
-2
Mass of electron
= 9.1 ? 10
-31
kg
Mass of neutron = 1.675 ? 10
-27
kg
Mass of proton = 1.673 ? 10
-27
kg
Avogadro’s number = 6.023 ? 10
23
per gram mole
Boltzmann constant = 1.38 ? 10
-23
J K
-1
CBSE XII | PHYSICS
Board Paper – 2019
SECTION – A
Q. 1 Draw a plot of resistivity versus temperature for a typical semiconductor. [1]
Q. 2 Define the term ‘attenuation’ in communication system. [1]
Q. 3 Two metallic spheres A and B kept on insulating stands are in contact with
each other. A positively charged rod P is brought near the sphere A as shown in the
figure. The two spheres are separated from each other, and the rod P is removed.
What will be the nature of charges on spheres A and B? [1]
OR
A metal sphere is kept on an insulating stand. A negatively charged rod is brought
near it, then the sphere is earthed as shown. On removing the earthing, and taking
the negatively charged rod away, what will be the nature of charge on the sphere?
Give reason for your answer.
Q. 4 In photoelectric emission, when the frequency of incident radiation in
Photoelectric effect is doubled, will the maximum kinetic energy of photoelectrons
also be doubled? Justify your answer. [1]
Page 3
CBSE XII | PHYSICS
Board Paper – 2019
CBSE
Class XII Physics
Board Paper - 2019
Time: 3 hours Maximum Marks: 70
General Instructions:
(i) All questions are compulsory. There are 27 questions in all.
(ii) This question paper has four sections: Section A, Section B, Section C, and
Section D.
(iii) Section A contains five questions of one mark each, section B contains seven
questions of two marks each, section C contains twelve questions of three
marks each, section D contains three questions of five marks each.
(iv) There is no overall choice. However, an internal choice has been provided in
two question of one mark, two question of two marks, four questions of
three marks and three questions of five marks weightage. You have to
attempt only one of the choices in such questions.
(v) You may use the following values of physical constants wherever necessary:
c = 3 ? 10
8
m/s
h = 6.63 ? 10
-34
Js
e = 1.6 ? 10
-19
C
µ
0
= 4 p ? 10
-7
T mA
-l
?
0
= 8.854 ? 10
-12
C
2
N
-1
m
-2
0
1
4 ??
= 9 ? 10
9
N m
2
C
-2
Mass of electron
= 9.1 ? 10
-31
kg
Mass of neutron = 1.675 ? 10
-27
kg
Mass of proton = 1.673 ? 10
-27
kg
Avogadro’s number = 6.023 ? 10
23
per gram mole
Boltzmann constant = 1.38 ? 10
-23
J K
-1
CBSE XII | PHYSICS
Board Paper – 2019
SECTION – A
Q. 1 Draw a plot of resistivity versus temperature for a typical semiconductor. [1]
Q. 2 Define the term ‘attenuation’ in communication system. [1]
Q. 3 Two metallic spheres A and B kept on insulating stands are in contact with
each other. A positively charged rod P is brought near the sphere A as shown in the
figure. The two spheres are separated from each other, and the rod P is removed.
What will be the nature of charges on spheres A and B? [1]
OR
A metal sphere is kept on an insulating stand. A negatively charged rod is brought
near it, then the sphere is earthed as shown. On removing the earthing, and taking
the negatively charged rod away, what will be the nature of charge on the sphere?
Give reason for your answer.
Q. 4 In photoelectric emission, when the frequency of incident radiation in
Photoelectric effect is doubled, will the maximum kinetic energy of photoelectrons
also be doubled? Justify your answer. [1]
CBSE XII | PHYSICS
Board Paper – 2019
Q. 5 State the condition under which a large magnification can be achieved in an
instrumental telescope
OR
How does the angle of minimum deviation of a glass prism vary if the incident violet
light is replaced by a red light? [1]
SECTION – B
Q. 6 show that image formed by convex mirror of an object is always virtual. [2]
Q. 7 Distinguish between nuclear fusion and nuclear fission. Give one example for
each. [2]
Q. 8 An electron in a hydrogen atom in the second excited state jumps to the first
and ground state of the atom. Find the ratio of the wavelengths excited during this
process. [2]
Q. 9 Five point charges, each of charge + q are placed on five vertices of a regular
hexagon of side ‘l’. Find the magnitude of the resultant force on a charge – q placed
at the centre of the hexagon. [2]
OR
A simple pendulum consists of small sphere of mass m suspended by a thread of
length l. The sphere carries a positive charge q. The pendulum is placed in a
uniform electric field of strength E directed vertically downwards. Find the period of
oscillation of the pendulum due to the electrostatic force acting on the sphere,
neglecting the effect of the gravitational force. [2]
Q. 10 Plot a graph showing the variation of undecayed nuclei N versus time t. From
the graph, find out how one can determine the half-life and average life of the
radioactive nuclei. [2]
Q. 11 A 0.5 m long solenoid of 10 turns/cm has area of cross-section 1 cm
2
.
Calculate the voltage induced across its ends if the current in the solenoid is
changed from 1 A to 2 A in 0.1 s. [2]
OR
Page 4
CBSE XII | PHYSICS
Board Paper – 2019
CBSE
Class XII Physics
Board Paper - 2019
Time: 3 hours Maximum Marks: 70
General Instructions:
(i) All questions are compulsory. There are 27 questions in all.
(ii) This question paper has four sections: Section A, Section B, Section C, and
Section D.
(iii) Section A contains five questions of one mark each, section B contains seven
questions of two marks each, section C contains twelve questions of three
marks each, section D contains three questions of five marks each.
(iv) There is no overall choice. However, an internal choice has been provided in
two question of one mark, two question of two marks, four questions of
three marks and three questions of five marks weightage. You have to
attempt only one of the choices in such questions.
(v) You may use the following values of physical constants wherever necessary:
c = 3 ? 10
8
m/s
h = 6.63 ? 10
-34
Js
e = 1.6 ? 10
-19
C
µ
0
= 4 p ? 10
-7
T mA
-l
?
0
= 8.854 ? 10
-12
C
2
N
-1
m
-2
0
1
4 ??
= 9 ? 10
9
N m
2
C
-2
Mass of electron
= 9.1 ? 10
-31
kg
Mass of neutron = 1.675 ? 10
-27
kg
Mass of proton = 1.673 ? 10
-27
kg
Avogadro’s number = 6.023 ? 10
23
per gram mole
Boltzmann constant = 1.38 ? 10
-23
J K
-1
CBSE XII | PHYSICS
Board Paper – 2019
SECTION – A
Q. 1 Draw a plot of resistivity versus temperature for a typical semiconductor. [1]
Q. 2 Define the term ‘attenuation’ in communication system. [1]
Q. 3 Two metallic spheres A and B kept on insulating stands are in contact with
each other. A positively charged rod P is brought near the sphere A as shown in the
figure. The two spheres are separated from each other, and the rod P is removed.
What will be the nature of charges on spheres A and B? [1]
OR
A metal sphere is kept on an insulating stand. A negatively charged rod is brought
near it, then the sphere is earthed as shown. On removing the earthing, and taking
the negatively charged rod away, what will be the nature of charge on the sphere?
Give reason for your answer.
Q. 4 In photoelectric emission, when the frequency of incident radiation in
Photoelectric effect is doubled, will the maximum kinetic energy of photoelectrons
also be doubled? Justify your answer. [1]
CBSE XII | PHYSICS
Board Paper – 2019
Q. 5 State the condition under which a large magnification can be achieved in an
instrumental telescope
OR
How does the angle of minimum deviation of a glass prism vary if the incident violet
light is replaced by a red light? [1]
SECTION – B
Q. 6 show that image formed by convex mirror of an object is always virtual. [2]
Q. 7 Distinguish between nuclear fusion and nuclear fission. Give one example for
each. [2]
Q. 8 An electron in a hydrogen atom in the second excited state jumps to the first
and ground state of the atom. Find the ratio of the wavelengths excited during this
process. [2]
Q. 9 Five point charges, each of charge + q are placed on five vertices of a regular
hexagon of side ‘l’. Find the magnitude of the resultant force on a charge – q placed
at the centre of the hexagon. [2]
OR
A simple pendulum consists of small sphere of mass m suspended by a thread of
length l. The sphere carries a positive charge q. The pendulum is placed in a
uniform electric field of strength E directed vertically downwards. Find the period of
oscillation of the pendulum due to the electrostatic force acting on the sphere,
neglecting the effect of the gravitational force. [2]
Q. 10 Plot a graph showing the variation of undecayed nuclei N versus time t. From
the graph, find out how one can determine the half-life and average life of the
radioactive nuclei. [2]
Q. 11 A 0.5 m long solenoid of 10 turns/cm has area of cross-section 1 cm
2
.
Calculate the voltage induced across its ends if the current in the solenoid is
changed from 1 A to 2 A in 0.1 s. [2]
OR
CBSE XII | PHYSICS
Board Paper – 2019
A small flat search coil of area 5 cm
2
with 140 closely wound turns is placed
between the poles of a powerful magnet producing magnetic field 0.09 T and then
quickly removed out of the field region. Calculate
(a) change of magnetic flux through the coil, and
(b) emf induced in the coil.
Q. 12 [2]
The figure shows a network of five capacitors connected to a 100 V supply.
Calculate the total energy stored in the network.
SECTION – C
Q. 13 In the circuit given below, find the voltmeter reading across a 4 O resistor. [3]
Q. 14 When a parallel plate capacitor is being charged by a dc battery, why does a
galvanometer show a momentary deflection?
Obtain the expression for the displacement current and show how it is related to
conduction current in a steady state. [3]
Page 5
CBSE XII | PHYSICS
Board Paper – 2019
CBSE
Class XII Physics
Board Paper - 2019
Time: 3 hours Maximum Marks: 70
General Instructions:
(i) All questions are compulsory. There are 27 questions in all.
(ii) This question paper has four sections: Section A, Section B, Section C, and
Section D.
(iii) Section A contains five questions of one mark each, section B contains seven
questions of two marks each, section C contains twelve questions of three
marks each, section D contains three questions of five marks each.
(iv) There is no overall choice. However, an internal choice has been provided in
two question of one mark, two question of two marks, four questions of
three marks and three questions of five marks weightage. You have to
attempt only one of the choices in such questions.
(v) You may use the following values of physical constants wherever necessary:
c = 3 ? 10
8
m/s
h = 6.63 ? 10
-34
Js
e = 1.6 ? 10
-19
C
µ
0
= 4 p ? 10
-7
T mA
-l
?
0
= 8.854 ? 10
-12
C
2
N
-1
m
-2
0
1
4 ??
= 9 ? 10
9
N m
2
C
-2
Mass of electron
= 9.1 ? 10
-31
kg
Mass of neutron = 1.675 ? 10
-27
kg
Mass of proton = 1.673 ? 10
-27
kg
Avogadro’s number = 6.023 ? 10
23
per gram mole
Boltzmann constant = 1.38 ? 10
-23
J K
-1
CBSE XII | PHYSICS
Board Paper – 2019
SECTION – A
Q. 1 Draw a plot of resistivity versus temperature for a typical semiconductor. [1]
Q. 2 Define the term ‘attenuation’ in communication system. [1]
Q. 3 Two metallic spheres A and B kept on insulating stands are in contact with
each other. A positively charged rod P is brought near the sphere A as shown in the
figure. The two spheres are separated from each other, and the rod P is removed.
What will be the nature of charges on spheres A and B? [1]
OR
A metal sphere is kept on an insulating stand. A negatively charged rod is brought
near it, then the sphere is earthed as shown. On removing the earthing, and taking
the negatively charged rod away, what will be the nature of charge on the sphere?
Give reason for your answer.
Q. 4 In photoelectric emission, when the frequency of incident radiation in
Photoelectric effect is doubled, will the maximum kinetic energy of photoelectrons
also be doubled? Justify your answer. [1]
CBSE XII | PHYSICS
Board Paper – 2019
Q. 5 State the condition under which a large magnification can be achieved in an
instrumental telescope
OR
How does the angle of minimum deviation of a glass prism vary if the incident violet
light is replaced by a red light? [1]
SECTION – B
Q. 6 show that image formed by convex mirror of an object is always virtual. [2]
Q. 7 Distinguish between nuclear fusion and nuclear fission. Give one example for
each. [2]
Q. 8 An electron in a hydrogen atom in the second excited state jumps to the first
and ground state of the atom. Find the ratio of the wavelengths excited during this
process. [2]
Q. 9 Five point charges, each of charge + q are placed on five vertices of a regular
hexagon of side ‘l’. Find the magnitude of the resultant force on a charge – q placed
at the centre of the hexagon. [2]
OR
A simple pendulum consists of small sphere of mass m suspended by a thread of
length l. The sphere carries a positive charge q. The pendulum is placed in a
uniform electric field of strength E directed vertically downwards. Find the period of
oscillation of the pendulum due to the electrostatic force acting on the sphere,
neglecting the effect of the gravitational force. [2]
Q. 10 Plot a graph showing the variation of undecayed nuclei N versus time t. From
the graph, find out how one can determine the half-life and average life of the
radioactive nuclei. [2]
Q. 11 A 0.5 m long solenoid of 10 turns/cm has area of cross-section 1 cm
2
.
Calculate the voltage induced across its ends if the current in the solenoid is
changed from 1 A to 2 A in 0.1 s. [2]
OR
CBSE XII | PHYSICS
Board Paper – 2019
A small flat search coil of area 5 cm
2
with 140 closely wound turns is placed
between the poles of a powerful magnet producing magnetic field 0.09 T and then
quickly removed out of the field region. Calculate
(a) change of magnetic flux through the coil, and
(b) emf induced in the coil.
Q. 12 [2]
The figure shows a network of five capacitors connected to a 100 V supply.
Calculate the total energy stored in the network.
SECTION – C
Q. 13 In the circuit given below, find the voltmeter reading across a 4 O resistor. [3]
Q. 14 When a parallel plate capacitor is being charged by a dc battery, why does a
galvanometer show a momentary deflection?
Obtain the expression for the displacement current and show how it is related to
conduction current in a steady state. [3]
CBSE XII | PHYSICS
Board Paper – 2019
Q. 15 [3]
a) An ac circuit as shown in the figure has an inductor of inductance L and a
resistor of resistance R connected in series. Using the phasor diagram, explain
why the voltage in the circuit will lead the current in phase.
b) The potential difference across the resistor is 160 V and that across the inductor
is 120 V. Find the effective value of the applied voltage. If the effective current
in the circuit be 1.0 A, calculate the total impedance of the circuit.
c) What will be the potential difference in the circuit when direct current is passed
through the circuit?
OR
An ac circuit consists of a series combination of circuit elements X and Y. The
current is ahead of the voltage in phase by
4
?
. If element X is a pure resistor of 100
O.
(a) Name the circuit element Y.
(b) Calculate the rms value of current, if rms value of voltage is 141 V.
(c) What will happen if the ac source is replaced by a dc source?
Q. 16 [3]
(a) Explain briefly, using a proper diagram the difference in behaviour of a
conductor and a dielectric in the presence of external electric field.
(b) Define the term polarization of a dielectric and write the expression for a linear
isotropic dielectric in terms of electric field.
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