Class 12 Physics: CBSE Sample Question Paper (2023-24) | Sample Papers for Class 12 Medical and Non-Medical PDF Download

 Page 1


Time Allowed: 3 hours Maximum Marks: 70 
General Instructions:
1. There are 33 questions in all. All questions are compulsory.
2. This question paper has five sections: Section A, Section B, Section C, Section D and Section E.
3. All the sections are compulsory.
4. Section A contains sixteen questions, twelve MCQ and four Assertion Reasoning based of 1 mark each, Section B
contains five questions of two marks each, Section C contains seven questions of three marks each, Section D
contains two case study based questions of four marks each and Section E contains three long answer questions of
five marks each.
5. There is no overall choice. However, an internal choice has been provided in one question in Section B, one
question in Section C, one question in each CBQ in Section D and all three questions in Section E. You have to
attempt only one of the choices in such questions.
6. Use of calculators is not allowed.
Section A
a)
3  10
19
 m
-3 b)
9  10
-5
 m
-3
c)
2.25  10
11
 m
-3 d)
5  10
9
 m
-3
1. Pure silicon at 300 K has equal electron (n
e
) and hole (n
h
) concentrations of 1.5  10
16
 m
-3
. Doping by indium
increases n
h
 to 4.5  10
22
 m
-3
. The n
e
 in the doped silicon is
[1]
× × × × × × a)
[ML
2
T
-3
A
1
]
b)
[ML
2
T
-3
A
-2
]
c)
[ML
3
T
-3
A
-2
]
d)
[ML
2
T
-3
A
-1
]
2. The dimension of electrical resistance is: [1]
a) No image is formed by the remaining
portion of the lens
b) Full image will be formed but will be less
bright
c) Two images will be formed d) Central portion of the image will be absent
3. How will the image formed by a convex lens be affected if the central portion of the lens is wrapped in a black
paper?
[1]
4. A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite
sides. Ratio of magnetic fields at these points will be 
[1]
Page 1 of 21
Page 2


Time Allowed: 3 hours Maximum Marks: 70 
General Instructions:
1. There are 33 questions in all. All questions are compulsory.
2. This question paper has five sections: Section A, Section B, Section C, Section D and Section E.
3. All the sections are compulsory.
4. Section A contains sixteen questions, twelve MCQ and four Assertion Reasoning based of 1 mark each, Section B
contains five questions of two marks each, Section C contains seven questions of three marks each, Section D
contains two case study based questions of four marks each and Section E contains three long answer questions of
five marks each.
5. There is no overall choice. However, an internal choice has been provided in one question in Section B, one
question in Section C, one question in each CBQ in Section D and all three questions in Section E. You have to
attempt only one of the choices in such questions.
6. Use of calculators is not allowed.
Section A
a)
3  10
19
 m
-3 b)
9  10
-5
 m
-3
c)
2.25  10
11
 m
-3 d)
5  10
9
 m
-3
1. Pure silicon at 300 K has equal electron (n
e
) and hole (n
h
) concentrations of 1.5  10
16
 m
-3
. Doping by indium
increases n
h
 to 4.5  10
22
 m
-3
. The n
e
 in the doped silicon is
[1]
× × × × × × a)
[ML
2
T
-3
A
1
]
b)
[ML
2
T
-3
A
-2
]
c)
[ML
3
T
-3
A
-2
]
d)
[ML
2
T
-3
A
-1
]
2. The dimension of electrical resistance is: [1]
a) No image is formed by the remaining
portion of the lens
b) Full image will be formed but will be less
bright
c) Two images will be formed d) Central portion of the image will be absent
3. How will the image formed by a convex lens be affected if the central portion of the lens is wrapped in a black
paper?
[1]
4. A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite
sides. Ratio of magnetic fields at these points will be 
[1]
Page 1 of 21
a) b) 4
c) 3 d) 8
1 2 2 v a) b)
c) d)
5. In which of the states shown in the figure, is potential energy of an electric dipole maximum? [1]
a) b)
c) d)
6. An electron having energy 10 eV is circulating in path of radius 0.105 m having magnetic field of 10
-4
T. The
speed of the electron will be:
[1]
1 . 9 × m / s 1 0 6 3 . 8 × m / s 1 0 1 2 1 . 9 × m / s 1 0 1 2 3 . 8 × m / s 1 0 6 a) the currents in the two coils b) the rates at which currents are changing in
the two coils
c) relative position and orientation of the two
coils
d) the material of the wires of the coils
7. Two coils are placed closed to each other. The mutual inductance of the pair of coils depends upon: [1]
a) 0.4 J/T b) 0.8 J/T
c) 0.6 J/T d) 0.5 J/T
8. A closely wound solenoid of 800 turns and area of cross section  carries a current of 3.0 A. What
is its associated magnetic moment?
[1] 2 . 5 × 1 0 - 4 m 2 a) k b)
c) d) zero
9. In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is  is
k ( being the wavelength of light used). The intensity at a point where the path difference is , will be
[1] ? ? ? 4 k 4 k 2 a) b)
c) d)
10. An uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force look like [1]
Page 2 of 21
Page 3


Time Allowed: 3 hours Maximum Marks: 70 
General Instructions:
1. There are 33 questions in all. All questions are compulsory.
2. This question paper has five sections: Section A, Section B, Section C, Section D and Section E.
3. All the sections are compulsory.
4. Section A contains sixteen questions, twelve MCQ and four Assertion Reasoning based of 1 mark each, Section B
contains five questions of two marks each, Section C contains seven questions of three marks each, Section D
contains two case study based questions of four marks each and Section E contains three long answer questions of
five marks each.
5. There is no overall choice. However, an internal choice has been provided in one question in Section B, one
question in Section C, one question in each CBQ in Section D and all three questions in Section E. You have to
attempt only one of the choices in such questions.
6. Use of calculators is not allowed.
Section A
a)
3  10
19
 m
-3 b)
9  10
-5
 m
-3
c)
2.25  10
11
 m
-3 d)
5  10
9
 m
-3
1. Pure silicon at 300 K has equal electron (n
e
) and hole (n
h
) concentrations of 1.5  10
16
 m
-3
. Doping by indium
increases n
h
 to 4.5  10
22
 m
-3
. The n
e
 in the doped silicon is
[1]
× × × × × × a)
[ML
2
T
-3
A
1
]
b)
[ML
2
T
-3
A
-2
]
c)
[ML
3
T
-3
A
-2
]
d)
[ML
2
T
-3
A
-1
]
2. The dimension of electrical resistance is: [1]
a) No image is formed by the remaining
portion of the lens
b) Full image will be formed but will be less
bright
c) Two images will be formed d) Central portion of the image will be absent
3. How will the image formed by a convex lens be affected if the central portion of the lens is wrapped in a black
paper?
[1]
4. A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite
sides. Ratio of magnetic fields at these points will be 
[1]
Page 1 of 21
a) b) 4
c) 3 d) 8
1 2 2 v a) b)
c) d)
5. In which of the states shown in the figure, is potential energy of an electric dipole maximum? [1]
a) b)
c) d)
6. An electron having energy 10 eV is circulating in path of radius 0.105 m having magnetic field of 10
-4
T. The
speed of the electron will be:
[1]
1 . 9 × m / s 1 0 6 3 . 8 × m / s 1 0 1 2 1 . 9 × m / s 1 0 1 2 3 . 8 × m / s 1 0 6 a) the currents in the two coils b) the rates at which currents are changing in
the two coils
c) relative position and orientation of the two
coils
d) the material of the wires of the coils
7. Two coils are placed closed to each other. The mutual inductance of the pair of coils depends upon: [1]
a) 0.4 J/T b) 0.8 J/T
c) 0.6 J/T d) 0.5 J/T
8. A closely wound solenoid of 800 turns and area of cross section  carries a current of 3.0 A. What
is its associated magnetic moment?
[1] 2 . 5 × 1 0 - 4 m 2 a) k b)
c) d) zero
9. In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is  is
k ( being the wavelength of light used). The intensity at a point where the path difference is , will be
[1] ? ? ? 4 k 4 k 2 a) b)
c) d)
10. An uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force look like [1]
Page 2 of 21
a) 0.04 A b) zero
c) 0.05 A d) 0.66 A
11. Assume that each diode shown in the figure has a forward bias resistance of 50 and an infinite reverse bias
resistance. The current through the 150 resistance is 
[1] O O a) 15 cm b) 21 cm
c) 18 cm d) 12 cm
12. A lamp and a screen are set up 100 cm apart and a convex lens is placed between them. The two positions of the
lens forming real images on the screen are 40 cm apart. What is the focal length of the lens?
[1]
a) Both A and R are true and R is the correct
explanation of A.
b) Both A and R are true but R is not the
correct explanation of A.
c) A is true but R is false. d) A is false but R is true.
13. Assertion (A): The process of photoelectric emission is different to that of thermionic emission. 
Reason (R): The process of thermionic emission is temperature-dependent but photoelectric emission is
independent of temperature.
[1]
a) Both A and R are true and R is the correct
explanation of A
b) Both A and R are true but R is NOT the
correct explanation of A
c) A is true but R is false d) A is false and R is also false
14. Assertion: When a capacitor is filled completely with a metallic slab its capacity becomes very large. 
Reason: Dielectric constant for metal is zero.
[1]
a) Both A and R are true and R is the correct
explanation of A
b) Both A and R are true but R is NOT the
correct explanation of A
c) A is true but R is false d) A is false and R is also false
15. Assertion (A): Young’s double slit experiment can be performed using a source of white light. 
Reason (R): The wavelength of red light is less than the wavelength of other colours in white light.
[1]
a) Both A and R are true and R is the correct
explanation of A.
b) Both A and R are true but R is not the
correct explanation of A.
c) A is true but R is false. d) A is false but R is true.
16. Assertion (A): If the frequency of the applied AC is doubled, then the power factor of a series R-L circuit
decreases. 
Reason (R): Power factor of series R-L circuit is given by .
[1]
c o s ? = 2 R + R 2 ? 2 L 2 Page 3 of 21
Page 4


Time Allowed: 3 hours Maximum Marks: 70 
General Instructions:
1. There are 33 questions in all. All questions are compulsory.
2. This question paper has five sections: Section A, Section B, Section C, Section D and Section E.
3. All the sections are compulsory.
4. Section A contains sixteen questions, twelve MCQ and four Assertion Reasoning based of 1 mark each, Section B
contains five questions of two marks each, Section C contains seven questions of three marks each, Section D
contains two case study based questions of four marks each and Section E contains three long answer questions of
five marks each.
5. There is no overall choice. However, an internal choice has been provided in one question in Section B, one
question in Section C, one question in each CBQ in Section D and all three questions in Section E. You have to
attempt only one of the choices in such questions.
6. Use of calculators is not allowed.
Section A
a)
3  10
19
 m
-3 b)
9  10
-5
 m
-3
c)
2.25  10
11
 m
-3 d)
5  10
9
 m
-3
1. Pure silicon at 300 K has equal electron (n
e
) and hole (n
h
) concentrations of 1.5  10
16
 m
-3
. Doping by indium
increases n
h
 to 4.5  10
22
 m
-3
. The n
e
 in the doped silicon is
[1]
× × × × × × a)
[ML
2
T
-3
A
1
]
b)
[ML
2
T
-3
A
-2
]
c)
[ML
3
T
-3
A
-2
]
d)
[ML
2
T
-3
A
-1
]
2. The dimension of electrical resistance is: [1]
a) No image is formed by the remaining
portion of the lens
b) Full image will be formed but will be less
bright
c) Two images will be formed d) Central portion of the image will be absent
3. How will the image formed by a convex lens be affected if the central portion of the lens is wrapped in a black
paper?
[1]
4. A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite
sides. Ratio of magnetic fields at these points will be 
[1]
Page 1 of 21
a) b) 4
c) 3 d) 8
1 2 2 v a) b)
c) d)
5. In which of the states shown in the figure, is potential energy of an electric dipole maximum? [1]
a) b)
c) d)
6. An electron having energy 10 eV is circulating in path of radius 0.105 m having magnetic field of 10
-4
T. The
speed of the electron will be:
[1]
1 . 9 × m / s 1 0 6 3 . 8 × m / s 1 0 1 2 1 . 9 × m / s 1 0 1 2 3 . 8 × m / s 1 0 6 a) the currents in the two coils b) the rates at which currents are changing in
the two coils
c) relative position and orientation of the two
coils
d) the material of the wires of the coils
7. Two coils are placed closed to each other. The mutual inductance of the pair of coils depends upon: [1]
a) 0.4 J/T b) 0.8 J/T
c) 0.6 J/T d) 0.5 J/T
8. A closely wound solenoid of 800 turns and area of cross section  carries a current of 3.0 A. What
is its associated magnetic moment?
[1] 2 . 5 × 1 0 - 4 m 2 a) k b)
c) d) zero
9. In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is  is
k ( being the wavelength of light used). The intensity at a point where the path difference is , will be
[1] ? ? ? 4 k 4 k 2 a) b)
c) d)
10. An uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force look like [1]
Page 2 of 21
a) 0.04 A b) zero
c) 0.05 A d) 0.66 A
11. Assume that each diode shown in the figure has a forward bias resistance of 50 and an infinite reverse bias
resistance. The current through the 150 resistance is 
[1] O O a) 15 cm b) 21 cm
c) 18 cm d) 12 cm
12. A lamp and a screen are set up 100 cm apart and a convex lens is placed between them. The two positions of the
lens forming real images on the screen are 40 cm apart. What is the focal length of the lens?
[1]
a) Both A and R are true and R is the correct
explanation of A.
b) Both A and R are true but R is not the
correct explanation of A.
c) A is true but R is false. d) A is false but R is true.
13. Assertion (A): The process of photoelectric emission is different to that of thermionic emission. 
Reason (R): The process of thermionic emission is temperature-dependent but photoelectric emission is
independent of temperature.
[1]
a) Both A and R are true and R is the correct
explanation of A
b) Both A and R are true but R is NOT the
correct explanation of A
c) A is true but R is false d) A is false and R is also false
14. Assertion: When a capacitor is filled completely with a metallic slab its capacity becomes very large. 
Reason: Dielectric constant for metal is zero.
[1]
a) Both A and R are true and R is the correct
explanation of A
b) Both A and R are true but R is NOT the
correct explanation of A
c) A is true but R is false d) A is false and R is also false
15. Assertion (A): Young’s double slit experiment can be performed using a source of white light. 
Reason (R): The wavelength of red light is less than the wavelength of other colours in white light.
[1]
a) Both A and R are true and R is the correct
explanation of A.
b) Both A and R are true but R is not the
correct explanation of A.
c) A is true but R is false. d) A is false but R is true.
16. Assertion (A): If the frequency of the applied AC is doubled, then the power factor of a series R-L circuit
decreases. 
Reason (R): Power factor of series R-L circuit is given by .
[1]
c o s ? = 2 R + R 2 ? 2 L 2 Page 3 of 21
Section B
Section C
17. Identify the electromagnetic waves whose wavelengths lie in the range.
i. 10
-11
 m <  < 10
-14
 m
ii. 10
-4
 m <  < 10
-6
 m 
Write one use of each.
[2]
? ? 18. A muon is a particle that has the same charge as an electron but is 200 times heavier than it. It we had an atom in
which the muon revolves around a proton instead of an electron, what would be the magnetic moment of the
muon in the ground state of such an atom?
[2]
19. Define barrier potential. Why does the thickness of the depletion layer in a p-n junction diode vary with increase
in reverse bias?
[2]
20. Consider two different hydrogen atoms. The electron in each atom is in an excited state possible for the electrons
to have different energies, but the same orbital angular momentum according to the Bohr model?
[2]
21. A coil of N turns and radius R carries a current T. It is unwound and rewound to make a square coil of side a
having the same number of turns (N). Keeping the current I same, find the ratio of the magnetic moments of the
square coil and the circular coil.
[2]
OR
Is the force between two parallel current-carrying wires affected by the nature of the dielectric medium between
them?
22. AB, BC, CD and DA are resistors of 1, 1, 2 and 2  respectively connected in series. Between A and C is a 1
volt cell of resistance 2 , A being positive. Between B and D is a 2 V cell of 1  resistance, B being positive.
Find the current in each branch of the circuit.
[3] O O O 23. Define the terms potential barrier and depletion region for a p-n junction diode. State how the thickness of the
depletion region will change when p-n junction diode is
i. forward biased and
ii. reverse biased
[3]
24. Draw the graph showing the variation of photoelectric current with anode potential of a photocell for
1. the same frequencies but different intensities I
3
 > I
2
 > I
1
 of incident radiation, and
2. the same intensity but different frequencies  of incident radiation.
[3]
> > ? 1 ? 2 ? 3 25. Plot a graph showing the variation of binding energy per nucleon as a function of mass number. Which property
of nuclear force explains the approximate constancy of binding energy in the range 30 < A < 170? 
How does one explain the release of energy in both processes of nuclear fission and fusion from the graph?
[3]
26. It is found experimentally that 13.6 eV energy is required to separate a hydrogen atom into a proton and an
electron. Compute the orbital radius and the velocity of the electron in a hydrogen atom.
[3]
27. Explain by drawing a suitable diagram that the interference pattern in a double-slit is actually a superposition of
single-slit diffraction from each slit. 
Write two basic features that distinguish the interference pattern from those seen in a coherently illuminated
single slit.
[3]
28. A rectangular loop of sides 8 cm and 2 cm with a small cut is moving out of a region of uniform magnetic field
of magnitude 0.3 tesla directed normal to the loop. What is the voltage developed across the cut if velocity of
loop is  in a direction normal to the (i) longer side (ii) shorter side of the loop? For how long does the
[3]
1 c m s - 1 Page 4 of 21
Page 5


Time Allowed: 3 hours Maximum Marks: 70 
General Instructions:
1. There are 33 questions in all. All questions are compulsory.
2. This question paper has five sections: Section A, Section B, Section C, Section D and Section E.
3. All the sections are compulsory.
4. Section A contains sixteen questions, twelve MCQ and four Assertion Reasoning based of 1 mark each, Section B
contains five questions of two marks each, Section C contains seven questions of three marks each, Section D
contains two case study based questions of four marks each and Section E contains three long answer questions of
five marks each.
5. There is no overall choice. However, an internal choice has been provided in one question in Section B, one
question in Section C, one question in each CBQ in Section D and all three questions in Section E. You have to
attempt only one of the choices in such questions.
6. Use of calculators is not allowed.
Section A
a)
3  10
19
 m
-3 b)
9  10
-5
 m
-3
c)
2.25  10
11
 m
-3 d)
5  10
9
 m
-3
1. Pure silicon at 300 K has equal electron (n
e
) and hole (n
h
) concentrations of 1.5  10
16
 m
-3
. Doping by indium
increases n
h
 to 4.5  10
22
 m
-3
. The n
e
 in the doped silicon is
[1]
× × × × × × a)
[ML
2
T
-3
A
1
]
b)
[ML
2
T
-3
A
-2
]
c)
[ML
3
T
-3
A
-2
]
d)
[ML
2
T
-3
A
-1
]
2. The dimension of electrical resistance is: [1]
a) No image is formed by the remaining
portion of the lens
b) Full image will be formed but will be less
bright
c) Two images will be formed d) Central portion of the image will be absent
3. How will the image formed by a convex lens be affected if the central portion of the lens is wrapped in a black
paper?
[1]
4. A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite
sides. Ratio of magnetic fields at these points will be 
[1]
Page 1 of 21
a) b) 4
c) 3 d) 8
1 2 2 v a) b)
c) d)
5. In which of the states shown in the figure, is potential energy of an electric dipole maximum? [1]
a) b)
c) d)
6. An electron having energy 10 eV is circulating in path of radius 0.105 m having magnetic field of 10
-4
T. The
speed of the electron will be:
[1]
1 . 9 × m / s 1 0 6 3 . 8 × m / s 1 0 1 2 1 . 9 × m / s 1 0 1 2 3 . 8 × m / s 1 0 6 a) the currents in the two coils b) the rates at which currents are changing in
the two coils
c) relative position and orientation of the two
coils
d) the material of the wires of the coils
7. Two coils are placed closed to each other. The mutual inductance of the pair of coils depends upon: [1]
a) 0.4 J/T b) 0.8 J/T
c) 0.6 J/T d) 0.5 J/T
8. A closely wound solenoid of 800 turns and area of cross section  carries a current of 3.0 A. What
is its associated magnetic moment?
[1] 2 . 5 × 1 0 - 4 m 2 a) k b)
c) d) zero
9. In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is  is
k ( being the wavelength of light used). The intensity at a point where the path difference is , will be
[1] ? ? ? 4 k 4 k 2 a) b)
c) d)
10. An uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force look like [1]
Page 2 of 21
a) 0.04 A b) zero
c) 0.05 A d) 0.66 A
11. Assume that each diode shown in the figure has a forward bias resistance of 50 and an infinite reverse bias
resistance. The current through the 150 resistance is 
[1] O O a) 15 cm b) 21 cm
c) 18 cm d) 12 cm
12. A lamp and a screen are set up 100 cm apart and a convex lens is placed between them. The two positions of the
lens forming real images on the screen are 40 cm apart. What is the focal length of the lens?
[1]
a) Both A and R are true and R is the correct
explanation of A.
b) Both A and R are true but R is not the
correct explanation of A.
c) A is true but R is false. d) A is false but R is true.
13. Assertion (A): The process of photoelectric emission is different to that of thermionic emission. 
Reason (R): The process of thermionic emission is temperature-dependent but photoelectric emission is
independent of temperature.
[1]
a) Both A and R are true and R is the correct
explanation of A
b) Both A and R are true but R is NOT the
correct explanation of A
c) A is true but R is false d) A is false and R is also false
14. Assertion: When a capacitor is filled completely with a metallic slab its capacity becomes very large. 
Reason: Dielectric constant for metal is zero.
[1]
a) Both A and R are true and R is the correct
explanation of A
b) Both A and R are true but R is NOT the
correct explanation of A
c) A is true but R is false d) A is false and R is also false
15. Assertion (A): Young’s double slit experiment can be performed using a source of white light. 
Reason (R): The wavelength of red light is less than the wavelength of other colours in white light.
[1]
a) Both A and R are true and R is the correct
explanation of A.
b) Both A and R are true but R is not the
correct explanation of A.
c) A is true but R is false. d) A is false but R is true.
16. Assertion (A): If the frequency of the applied AC is doubled, then the power factor of a series R-L circuit
decreases. 
Reason (R): Power factor of series R-L circuit is given by .
[1]
c o s ? = 2 R + R 2 ? 2 L 2 Page 3 of 21
Section B
Section C
17. Identify the electromagnetic waves whose wavelengths lie in the range.
i. 10
-11
 m <  < 10
-14
 m
ii. 10
-4
 m <  < 10
-6
 m 
Write one use of each.
[2]
? ? 18. A muon is a particle that has the same charge as an electron but is 200 times heavier than it. It we had an atom in
which the muon revolves around a proton instead of an electron, what would be the magnetic moment of the
muon in the ground state of such an atom?
[2]
19. Define barrier potential. Why does the thickness of the depletion layer in a p-n junction diode vary with increase
in reverse bias?
[2]
20. Consider two different hydrogen atoms. The electron in each atom is in an excited state possible for the electrons
to have different energies, but the same orbital angular momentum according to the Bohr model?
[2]
21. A coil of N turns and radius R carries a current T. It is unwound and rewound to make a square coil of side a
having the same number of turns (N). Keeping the current I same, find the ratio of the magnetic moments of the
square coil and the circular coil.
[2]
OR
Is the force between two parallel current-carrying wires affected by the nature of the dielectric medium between
them?
22. AB, BC, CD and DA are resistors of 1, 1, 2 and 2  respectively connected in series. Between A and C is a 1
volt cell of resistance 2 , A being positive. Between B and D is a 2 V cell of 1  resistance, B being positive.
Find the current in each branch of the circuit.
[3] O O O 23. Define the terms potential barrier and depletion region for a p-n junction diode. State how the thickness of the
depletion region will change when p-n junction diode is
i. forward biased and
ii. reverse biased
[3]
24. Draw the graph showing the variation of photoelectric current with anode potential of a photocell for
1. the same frequencies but different intensities I
3
 > I
2
 > I
1
 of incident radiation, and
2. the same intensity but different frequencies  of incident radiation.
[3]
> > ? 1 ? 2 ? 3 25. Plot a graph showing the variation of binding energy per nucleon as a function of mass number. Which property
of nuclear force explains the approximate constancy of binding energy in the range 30 < A < 170? 
How does one explain the release of energy in both processes of nuclear fission and fusion from the graph?
[3]
26. It is found experimentally that 13.6 eV energy is required to separate a hydrogen atom into a proton and an
electron. Compute the orbital radius and the velocity of the electron in a hydrogen atom.
[3]
27. Explain by drawing a suitable diagram that the interference pattern in a double-slit is actually a superposition of
single-slit diffraction from each slit. 
Write two basic features that distinguish the interference pattern from those seen in a coherently illuminated
single slit.
[3]
28. A rectangular loop of sides 8 cm and 2 cm with a small cut is moving out of a region of uniform magnetic field
of magnitude 0.3 tesla directed normal to the loop. What is the voltage developed across the cut if velocity of
loop is  in a direction normal to the (i) longer side (ii) shorter side of the loop? For how long does the
[3]
1 c m s - 1 Page 4 of 21
Section D
induced voltage last in each case? 
OR
The current flowing through an inductor of self-inductance L is continuously increasing. Plot a graph showing the
variation of:
i. Magnetic flux versus the current
ii. Induced emf versus dI/dt
iii. Magnetic potential energy stored versus the current.
29. Read the text carefully and answer the questions:
Maxwell showed that the speed of an electromagnetic wave depends on the permeability and permittivity of the
medium through which it travels. The speed of an electromagnetic wave in free space is given by c = . The
fact led Maxwell to predict that light is an electromagnetic wave. The emergence of the speed of light from
purely electromagnetic considerations is the crowning achievement of Maxwell’s electromagnetic theory. The
speed of an electromagnetic wave in any medium of permeability  and permittivity  will be  where K is
the dielectric constant of the medium and  is the relative permeability.
[4]
OR
1 µ 0 e 0 v µ e c K µ r v µ r a)
MLT
-1 b)
ML
-1
T
-2
c)
ML
2
T
-2 d)
ML
2
T
-1
The dimensions of  ( : permittivity of free space; E = electric field) is (i)
1 2 e 0 E 2 e 0 a)
 = ML
2
T
-1 b)
 = MLT
-2
A
-2
c)
 = M
-1
L
-3
T
4
A
2 d)
 = M
-1
L
-3
T
2
A
Let  denote the dimensional formula of the permittivity of the vacuum. If M = mass, L = length, T =
time and A = electric current, then
(ii) [ ] e 0 [ ] e 0 [ ] e 0 [ ] e 0 [ ] e 0 a) wavelength is halved and the frequency
remains unchanged.
b) wavelength and frequency both remain
unchanged
c) wavelength is doubled and the
frequency remains unchanged
d) wavelength is doubled and the
frequency becomes half
An electromagnetic wave of frequency 3 MHz passes from vacuum into a dielectric medium with
permittivity  = 4. Then
(iii)
e Page 5 of 21