Physics: Sample Question Paper- 4, Class 12 | Physics for Grade 12 PDF Download

 Page 1


  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
CBSE Board 
Class XII Physics 
Sample Paper - 4 
 
Time:  Three Hours Maximum Marks: 70 
 
General Instructions 
(a) All questions are compulsory. 
(b) There are 29 questions in total. Questions 1 to 8 carry one mark each, questions 9 to 
16 carry two marks each, questions 17 to 25 carry three marks each and questions 
27 to 29 carry five marks each. 
(c) Question 26 is a value based question carrying four marks. 
(d) There is no overall choice. However, an internal choice has been provided in one 
question of two marks, one question of three marks and all three questions of five 
marks each. You have to attempt only one of the given choices in such questions. 
(e) Use of calculator is not permitted. 
(f) You may use the following physical constants wherever necessary. 
-1
-1
-1
19
8
34
7
23
23
27
 C
 m s
 J s
 T ma
 J K
 /mole
 kg
1.6 10
3 10
6.6 10
4 10
1.38 10
6.023 10
1.6 10
?
?
?
?
??
??
??
??
??
??
??
o
B
A
n
e
c
h
K
N
m
?? 
 
 
1. Suppose one proton A and one electron B are placed between two parallel plates having 
a potential difference V as shown in the figure. 
 
 Will A and B experience equal or unequal force?  (1) 
Page 2


  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
CBSE Board 
Class XII Physics 
Sample Paper - 4 
 
Time:  Three Hours Maximum Marks: 70 
 
General Instructions 
(a) All questions are compulsory. 
(b) There are 29 questions in total. Questions 1 to 8 carry one mark each, questions 9 to 
16 carry two marks each, questions 17 to 25 carry three marks each and questions 
27 to 29 carry five marks each. 
(c) Question 26 is a value based question carrying four marks. 
(d) There is no overall choice. However, an internal choice has been provided in one 
question of two marks, one question of three marks and all three questions of five 
marks each. You have to attempt only one of the given choices in such questions. 
(e) Use of calculator is not permitted. 
(f) You may use the following physical constants wherever necessary. 
-1
-1
-1
19
8
34
7
23
23
27
 C
 m s
 J s
 T ma
 J K
 /mole
 kg
1.6 10
3 10
6.6 10
4 10
1.38 10
6.023 10
1.6 10
?
?
?
?
??
??
??
??
??
??
??
o
B
A
n
e
c
h
K
N
m
?? 
 
 
1. Suppose one proton A and one electron B are placed between two parallel plates having 
a potential difference V as shown in the figure. 
 
 Will A and B experience equal or unequal force?  (1) 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
2. An electron and a proton moving with the same speed enter the same magnetic field at 
right angles to the direction of the field. For which of the two particles will the radius of 
circular path be smaller?  (1) 
3. For which frequency of light is the human eye most sensitive?  (1) 
4. The electric current in a wire in the direction from B to A is decreasing. What is the 
direction of induced current in the metallic loop kept above the wire as shown2in the 
figure?  (1) 
 
 
5. A lens of focal length 30 cm is cut vertically as shown in figure. What will be the new 
focal length?  (1) 
 
 
 
6. Are matter waves electromagnetic wave? Write de Broglie wave equation. (1) 
7. Why a transistor can/cannot be used as a rectifier? (1) 
8. What will happen if energy of the electron orbiting around nucleus becomes positive?  
 (1) 
9. Name the dielectric whose molecules have (i) non- zero (ii) zero dipole moment. Define 
the term ‘dielectric constant’ for a medium.  (2) 
 
 
Page 3


  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
CBSE Board 
Class XII Physics 
Sample Paper - 4 
 
Time:  Three Hours Maximum Marks: 70 
 
General Instructions 
(a) All questions are compulsory. 
(b) There are 29 questions in total. Questions 1 to 8 carry one mark each, questions 9 to 
16 carry two marks each, questions 17 to 25 carry three marks each and questions 
27 to 29 carry five marks each. 
(c) Question 26 is a value based question carrying four marks. 
(d) There is no overall choice. However, an internal choice has been provided in one 
question of two marks, one question of three marks and all three questions of five 
marks each. You have to attempt only one of the given choices in such questions. 
(e) Use of calculator is not permitted. 
(f) You may use the following physical constants wherever necessary. 
-1
-1
-1
19
8
34
7
23
23
27
 C
 m s
 J s
 T ma
 J K
 /mole
 kg
1.6 10
3 10
6.6 10
4 10
1.38 10
6.023 10
1.6 10
?
?
?
?
??
??
??
??
??
??
??
o
B
A
n
e
c
h
K
N
m
?? 
 
 
1. Suppose one proton A and one electron B are placed between two parallel plates having 
a potential difference V as shown in the figure. 
 
 Will A and B experience equal or unequal force?  (1) 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
2. An electron and a proton moving with the same speed enter the same magnetic field at 
right angles to the direction of the field. For which of the two particles will the radius of 
circular path be smaller?  (1) 
3. For which frequency of light is the human eye most sensitive?  (1) 
4. The electric current in a wire in the direction from B to A is decreasing. What is the 
direction of induced current in the metallic loop kept above the wire as shown2in the 
figure?  (1) 
 
 
5. A lens of focal length 30 cm is cut vertically as shown in figure. What will be the new 
focal length?  (1) 
 
 
 
6. Are matter waves electromagnetic wave? Write de Broglie wave equation. (1) 
7. Why a transistor can/cannot be used as a rectifier? (1) 
8. What will happen if energy of the electron orbiting around nucleus becomes positive?  
 (1) 
9. Name the dielectric whose molecules have (i) non- zero (ii) zero dipole moment. Define 
the term ‘dielectric constant’ for a medium.  (2) 
 
 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
10. Two hollow spheres of radius r 1 and r 2 are given. The space between them is filled with 
material of resistivity 
? ? ? as shown. Calculate its resistance.  (2) 
 
11. A current carrying solenoid contracts in length. Why?  (2) 
12. An A.C. voltage sin
o
E E wt ? is applied across an inductor L. Obtain an expression for 
the current I.  (2) 
13. How much work is required to be done to reduce the separation between two like 
charges of magnitude 100 C ? each from 20 cm to 10 cm?  (2) 
14. Why is spark produced in the switch, when the light is put off?  (2) 
OR 
An iron bar falling through a hollow region of a thick cylindrical shell made of copper 
experiences a retarding force. What can you conclude about the nature of the iron bar? (2) 
 
15. Show that only an accelerated charge can produce an electromagnetic wave.  (2) 
 
16.  An eye- piece of a telescope consists of two Plano – convex lenses 
12
and LL each of 
focal length f  separated by a distance of 2 3. f Where should 
1
L be placed relative to 
the focus of the objective lens of the telescope so that the final image through
2
L is seen 
at infinity?  (2) 
 
17. A tank is filled with water to a height of 12.5 cm. The apparent depth of a needle lying at 
the bottom of the beaker is measured by a microscope to be 9.4 cm. What is the 
refractive index of water? If water is replaced by a liquid of refractive index 1.63 up to 
the same height. By what distance would the microscope have to be moved to focus on 
the needle again?  (3) 
 
Page 4


  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
CBSE Board 
Class XII Physics 
Sample Paper - 4 
 
Time:  Three Hours Maximum Marks: 70 
 
General Instructions 
(a) All questions are compulsory. 
(b) There are 29 questions in total. Questions 1 to 8 carry one mark each, questions 9 to 
16 carry two marks each, questions 17 to 25 carry three marks each and questions 
27 to 29 carry five marks each. 
(c) Question 26 is a value based question carrying four marks. 
(d) There is no overall choice. However, an internal choice has been provided in one 
question of two marks, one question of three marks and all three questions of five 
marks each. You have to attempt only one of the given choices in such questions. 
(e) Use of calculator is not permitted. 
(f) You may use the following physical constants wherever necessary. 
-1
-1
-1
19
8
34
7
23
23
27
 C
 m s
 J s
 T ma
 J K
 /mole
 kg
1.6 10
3 10
6.6 10
4 10
1.38 10
6.023 10
1.6 10
?
?
?
?
??
??
??
??
??
??
??
o
B
A
n
e
c
h
K
N
m
?? 
 
 
1. Suppose one proton A and one electron B are placed between two parallel plates having 
a potential difference V as shown in the figure. 
 
 Will A and B experience equal or unequal force?  (1) 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
2. An electron and a proton moving with the same speed enter the same magnetic field at 
right angles to the direction of the field. For which of the two particles will the radius of 
circular path be smaller?  (1) 
3. For which frequency of light is the human eye most sensitive?  (1) 
4. The electric current in a wire in the direction from B to A is decreasing. What is the 
direction of induced current in the metallic loop kept above the wire as shown2in the 
figure?  (1) 
 
 
5. A lens of focal length 30 cm is cut vertically as shown in figure. What will be the new 
focal length?  (1) 
 
 
 
6. Are matter waves electromagnetic wave? Write de Broglie wave equation. (1) 
7. Why a transistor can/cannot be used as a rectifier? (1) 
8. What will happen if energy of the electron orbiting around nucleus becomes positive?  
 (1) 
9. Name the dielectric whose molecules have (i) non- zero (ii) zero dipole moment. Define 
the term ‘dielectric constant’ for a medium.  (2) 
 
 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
10. Two hollow spheres of radius r 1 and r 2 are given. The space between them is filled with 
material of resistivity 
? ? ? as shown. Calculate its resistance.  (2) 
 
11. A current carrying solenoid contracts in length. Why?  (2) 
12. An A.C. voltage sin
o
E E wt ? is applied across an inductor L. Obtain an expression for 
the current I.  (2) 
13. How much work is required to be done to reduce the separation between two like 
charges of magnitude 100 C ? each from 20 cm to 10 cm?  (2) 
14. Why is spark produced in the switch, when the light is put off?  (2) 
OR 
An iron bar falling through a hollow region of a thick cylindrical shell made of copper 
experiences a retarding force. What can you conclude about the nature of the iron bar? (2) 
 
15. Show that only an accelerated charge can produce an electromagnetic wave.  (2) 
 
16.  An eye- piece of a telescope consists of two Plano – convex lenses 
12
and LL each of 
focal length f  separated by a distance of 2 3. f Where should 
1
L be placed relative to 
the focus of the objective lens of the telescope so that the final image through
2
L is seen 
at infinity?  (2) 
 
17. A tank is filled with water to a height of 12.5 cm. The apparent depth of a needle lying at 
the bottom of the beaker is measured by a microscope to be 9.4 cm. What is the 
refractive index of water? If water is replaced by a liquid of refractive index 1.63 up to 
the same height. By what distance would the microscope have to be moved to focus on 
the needle again?  (3) 
 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
18.  Calculate capacitance of capacitor as shown below.  (3) 
 
OR 
A conducting slab of thickness ‘t’ is introduced without touching between the plates of a 
parallel plate capacitor, separated by a distance ‘d’ (t < d). Derive an expression for the 
capacitance of the capacitor.  (3) 
 
19. In the following circuit, the transistor used has a 100. ? ? Find , , and
BE CE BC
V V V 
for 2 ?
c
I mA.  (3) 
 
20. An electron and a photon each have a wavelength of 1 nm.  (3) 
Find  
i) Their momenta 
ii) Energy of photon 
iii) Kinetic energy of electron 
 
21.  A potential difference of V volts is applied to a conductor of length L and diameter D. 
How are the electric field and resistance of the conductor affected when in turn 
i) V is halved 
ii) L is doubled 
iii) D is halved  (3) 
Page 5


  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
CBSE Board 
Class XII Physics 
Sample Paper - 4 
 
Time:  Three Hours Maximum Marks: 70 
 
General Instructions 
(a) All questions are compulsory. 
(b) There are 29 questions in total. Questions 1 to 8 carry one mark each, questions 9 to 
16 carry two marks each, questions 17 to 25 carry three marks each and questions 
27 to 29 carry five marks each. 
(c) Question 26 is a value based question carrying four marks. 
(d) There is no overall choice. However, an internal choice has been provided in one 
question of two marks, one question of three marks and all three questions of five 
marks each. You have to attempt only one of the given choices in such questions. 
(e) Use of calculator is not permitted. 
(f) You may use the following physical constants wherever necessary. 
-1
-1
-1
19
8
34
7
23
23
27
 C
 m s
 J s
 T ma
 J K
 /mole
 kg
1.6 10
3 10
6.6 10
4 10
1.38 10
6.023 10
1.6 10
?
?
?
?
??
??
??
??
??
??
??
o
B
A
n
e
c
h
K
N
m
?? 
 
 
1. Suppose one proton A and one electron B are placed between two parallel plates having 
a potential difference V as shown in the figure. 
 
 Will A and B experience equal or unequal force?  (1) 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
2. An electron and a proton moving with the same speed enter the same magnetic field at 
right angles to the direction of the field. For which of the two particles will the radius of 
circular path be smaller?  (1) 
3. For which frequency of light is the human eye most sensitive?  (1) 
4. The electric current in a wire in the direction from B to A is decreasing. What is the 
direction of induced current in the metallic loop kept above the wire as shown2in the 
figure?  (1) 
 
 
5. A lens of focal length 30 cm is cut vertically as shown in figure. What will be the new 
focal length?  (1) 
 
 
 
6. Are matter waves electromagnetic wave? Write de Broglie wave equation. (1) 
7. Why a transistor can/cannot be used as a rectifier? (1) 
8. What will happen if energy of the electron orbiting around nucleus becomes positive?  
 (1) 
9. Name the dielectric whose molecules have (i) non- zero (ii) zero dipole moment. Define 
the term ‘dielectric constant’ for a medium.  (2) 
 
 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
10. Two hollow spheres of radius r 1 and r 2 are given. The space between them is filled with 
material of resistivity 
? ? ? as shown. Calculate its resistance.  (2) 
 
11. A current carrying solenoid contracts in length. Why?  (2) 
12. An A.C. voltage sin
o
E E wt ? is applied across an inductor L. Obtain an expression for 
the current I.  (2) 
13. How much work is required to be done to reduce the separation between two like 
charges of magnitude 100 C ? each from 20 cm to 10 cm?  (2) 
14. Why is spark produced in the switch, when the light is put off?  (2) 
OR 
An iron bar falling through a hollow region of a thick cylindrical shell made of copper 
experiences a retarding force. What can you conclude about the nature of the iron bar? (2) 
 
15. Show that only an accelerated charge can produce an electromagnetic wave.  (2) 
 
16.  An eye- piece of a telescope consists of two Plano – convex lenses 
12
and LL each of 
focal length f  separated by a distance of 2 3. f Where should 
1
L be placed relative to 
the focus of the objective lens of the telescope so that the final image through
2
L is seen 
at infinity?  (2) 
 
17. A tank is filled with water to a height of 12.5 cm. The apparent depth of a needle lying at 
the bottom of the beaker is measured by a microscope to be 9.4 cm. What is the 
refractive index of water? If water is replaced by a liquid of refractive index 1.63 up to 
the same height. By what distance would the microscope have to be moved to focus on 
the needle again?  (3) 
 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
18.  Calculate capacitance of capacitor as shown below.  (3) 
 
OR 
A conducting slab of thickness ‘t’ is introduced without touching between the plates of a 
parallel plate capacitor, separated by a distance ‘d’ (t < d). Derive an expression for the 
capacitance of the capacitor.  (3) 
 
19. In the following circuit, the transistor used has a 100. ? ? Find , , and
BE CE BC
V V V 
for 2 ?
c
I mA.  (3) 
 
20. An electron and a photon each have a wavelength of 1 nm.  (3) 
Find  
i) Their momenta 
ii) Energy of photon 
iii) Kinetic energy of electron 
 
21.  A potential difference of V volts is applied to a conductor of length L and diameter D. 
How are the electric field and resistance of the conductor affected when in turn 
i) V is halved 
ii) L is doubled 
iii) D is halved  (3) 
  
 
CBSE XII  |  PHYSICS 
Sample Paper – 4 
 
     
22.  The energy levels of an atom of element are shown in the following diagram. Which one 
of the level transitions will result in the emission of photons of wavelength 620 nm?  (3) 
 
 
23.  Explain the terms (i) pulse – amplitude modulation (PAM) and (ii) pulse – code 
modulations (PCM). Which modulation is preferred in transmitting signals and why? (3) 
 
24.  Show how the following gates can be obtained by using NAND gates only (i) OR gate (ii) 
AND gate (iii) Not gate  (3) 
 
25. Derive an expression for the equivalent emf and the equivalent internal resistance of a 
series combination of n cells in an electric circuit.  (3) 
 
26. Two best friends John and Jolly are students of IX class. John wants to be an astronaut 
but he does not know anything about astronomy. So, he shared his desire with his 
friend Jolly. Jolly asked him to take advice from his teacher.  
(i) What would be the suggestion of his teacher? 
(ii) An astronaut is looking down on earth's surface from a space shuttle at an altitude 
of 400 km. Assuming that the astronaut's pupil diameter is 5 mm and the 
wavelength of visible light is 500 nm. The astronaut will be able to resolve linear 
objects of about what size?  (4) 
27.  
(a) Estimate the average drift speed of conduction electrons in a copper wire of cross – 
sectional area 1.0 x 10
-7
 m
2
 carrying a current of 1.5 A. Assume that each copper 
atom contributes roughly one conduction electron. The density of copper is 
33
9.0 10 , kg m ? and its atomic mass is 63.5 u.