Sample Solution Paper 7: Physics, Class 11 Notes | EduRev

 Page 1


  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
CBSE Board 
Class XI Physics 
Sample Paper-7 Solution 
 
 
1.  
Second is the fundamental unit of time and is now defined as the duration of 2,192,631770 
vibrations of caesium -133.  
 
2.  
By lowering his hands, the cricket player increases the interval in which the catch is taken. 
This increase in time interval results in the lesser rate of change of momentum. Therefore, 
in accordance with Newton's second law of motion, lesser force acts on his hands and the 
player saves himself from being hurt.  
 
3.  
In fact friction is necessary evil. In case friction is not there, we cannot walk, we cannot 
travel in vehicles, we cannot light a match-stick, etc. Thus friction plays a very important 
role in our daily life.  
 
4. 
  
 
5.  
Angular momentum and linear momentum remain constant.  
 
6.  
Steel is more elastic than rubber, because the inter-atomic bonding strength is more in 
steel than that of rubber.  
 
 
 
 
Page 2


  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
CBSE Board 
Class XI Physics 
Sample Paper-7 Solution 
 
 
1.  
Second is the fundamental unit of time and is now defined as the duration of 2,192,631770 
vibrations of caesium -133.  
 
2.  
By lowering his hands, the cricket player increases the interval in which the catch is taken. 
This increase in time interval results in the lesser rate of change of momentum. Therefore, 
in accordance with Newton's second law of motion, lesser force acts on his hands and the 
player saves himself from being hurt.  
 
3.  
In fact friction is necessary evil. In case friction is not there, we cannot walk, we cannot 
travel in vehicles, we cannot light a match-stick, etc. Thus friction plays a very important 
role in our daily life.  
 
4. 
  
 
5.  
Angular momentum and linear momentum remain constant.  
 
6.  
Steel is more elastic than rubber, because the inter-atomic bonding strength is more in 
steel than that of rubber.  
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
7.  
Yes, during the change of state (such as melting of ice, boiling of water, etc.) the system 
absorbs heat but its temperature does not change. In this case, only the internal energy 
changes.  
 
8.  
  
 
9.  
The tip of the sharp pin is in the range of 10
-5
 to 10
-4
 m. The size of the nucleus is of the 
order of 10
-15
 to 10
-14
 m. Therefore, when the size of the nucleus is scaled up to the tip, we 
are scaling by a factor of 10
10
. Accordingly, the size of the atom will become 10
10
 x 10
-10
 = 1 
m.  
 
10.  
 
 
 
 
 
 
 
 
Page 3


  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
CBSE Board 
Class XI Physics 
Sample Paper-7 Solution 
 
 
1.  
Second is the fundamental unit of time and is now defined as the duration of 2,192,631770 
vibrations of caesium -133.  
 
2.  
By lowering his hands, the cricket player increases the interval in which the catch is taken. 
This increase in time interval results in the lesser rate of change of momentum. Therefore, 
in accordance with Newton's second law of motion, lesser force acts on his hands and the 
player saves himself from being hurt.  
 
3.  
In fact friction is necessary evil. In case friction is not there, we cannot walk, we cannot 
travel in vehicles, we cannot light a match-stick, etc. Thus friction plays a very important 
role in our daily life.  
 
4. 
  
 
5.  
Angular momentum and linear momentum remain constant.  
 
6.  
Steel is more elastic than rubber, because the inter-atomic bonding strength is more in 
steel than that of rubber.  
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
7.  
Yes, during the change of state (such as melting of ice, boiling of water, etc.) the system 
absorbs heat but its temperature does not change. In this case, only the internal energy 
changes.  
 
8.  
  
 
9.  
The tip of the sharp pin is in the range of 10
-5
 to 10
-4
 m. The size of the nucleus is of the 
order of 10
-15
 to 10
-14
 m. Therefore, when the size of the nucleus is scaled up to the tip, we 
are scaling by a factor of 10
10
. Accordingly, the size of the atom will become 10
10
 x 10
-10
 = 1 
m.  
 
10.  
 
 
 
 
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
11. 
The resultant displacement due to 12 m towards east and 5 m towards north (which are at 
90
o
 to each other) lies in the plane of paper and is given by. 
  
Displacement 6 m is vertically upward perpendicular to the plane of paper. Therefore, the 
angle between R 1 and 6 m is 90º.The resultant of these to (say R 2) will be 
     
 
12.  
(i) Work done by the centripetal force is always zero. 
(ii)  When a person does not move from his position, but he may be holding any amount 
of load, the work done is zero. Similarly, when a coolie travels on a platform with some 
load on his head, work done by him is zero. 
 
13.  
(a) 6.67 × 10
-11
 Nm
2
kg
-2
 
(b) It is defined as the gravitational force of attraction between two bodies, each of 
mass 1 kg, separated by a distance of 1 m.  
 
14. 
(a) Pressure x Volume = Constant 
Or PV = Constant 
 
(b) Work done is 
 W = 2.3026 nRT log 10(V 2/V 1) 
 
Where R is the universal gas constant, n is the number of moles of gas, T is the absolute 
temperature,V 1 is the initial volume and V 2 is the final volume of the gas. 
 
 
 
 
Page 4


  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
CBSE Board 
Class XI Physics 
Sample Paper-7 Solution 
 
 
1.  
Second is the fundamental unit of time and is now defined as the duration of 2,192,631770 
vibrations of caesium -133.  
 
2.  
By lowering his hands, the cricket player increases the interval in which the catch is taken. 
This increase in time interval results in the lesser rate of change of momentum. Therefore, 
in accordance with Newton's second law of motion, lesser force acts on his hands and the 
player saves himself from being hurt.  
 
3.  
In fact friction is necessary evil. In case friction is not there, we cannot walk, we cannot 
travel in vehicles, we cannot light a match-stick, etc. Thus friction plays a very important 
role in our daily life.  
 
4. 
  
 
5.  
Angular momentum and linear momentum remain constant.  
 
6.  
Steel is more elastic than rubber, because the inter-atomic bonding strength is more in 
steel than that of rubber.  
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
7.  
Yes, during the change of state (such as melting of ice, boiling of water, etc.) the system 
absorbs heat but its temperature does not change. In this case, only the internal energy 
changes.  
 
8.  
  
 
9.  
The tip of the sharp pin is in the range of 10
-5
 to 10
-4
 m. The size of the nucleus is of the 
order of 10
-15
 to 10
-14
 m. Therefore, when the size of the nucleus is scaled up to the tip, we 
are scaling by a factor of 10
10
. Accordingly, the size of the atom will become 10
10
 x 10
-10
 = 1 
m.  
 
10.  
 
 
 
 
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
11. 
The resultant displacement due to 12 m towards east and 5 m towards north (which are at 
90
o
 to each other) lies in the plane of paper and is given by. 
  
Displacement 6 m is vertically upward perpendicular to the plane of paper. Therefore, the 
angle between R 1 and 6 m is 90º.The resultant of these to (say R 2) will be 
     
 
12.  
(i) Work done by the centripetal force is always zero. 
(ii)  When a person does not move from his position, but he may be holding any amount 
of load, the work done is zero. Similarly, when a coolie travels on a platform with some 
load on his head, work done by him is zero. 
 
13.  
(a) 6.67 × 10
-11
 Nm
2
kg
-2
 
(b) It is defined as the gravitational force of attraction between two bodies, each of 
mass 1 kg, separated by a distance of 1 m.  
 
14. 
(a) Pressure x Volume = Constant 
Or PV = Constant 
 
(b) Work done is 
 W = 2.3026 nRT log 10(V 2/V 1) 
 
Where R is the universal gas constant, n is the number of moles of gas, T is the absolute 
temperature,V 1 is the initial volume and V 2 is the final volume of the gas. 
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
OR 
We know that, PV RT ? 
We are given 
2
costant VP ?     
2
constant
RT
V
V
??
??
??
??
 
 
2
constant
T
V
?      
Using 
22
1
1
TT
VV
?       
We get, 
2
22
1
22
T
T V T
V
? ? ? 
 
1
2 TT ?      
 
15.  
 
 
 
 
 
 
 
 
 
 
Page 5


  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
CBSE Board 
Class XI Physics 
Sample Paper-7 Solution 
 
 
1.  
Second is the fundamental unit of time and is now defined as the duration of 2,192,631770 
vibrations of caesium -133.  
 
2.  
By lowering his hands, the cricket player increases the interval in which the catch is taken. 
This increase in time interval results in the lesser rate of change of momentum. Therefore, 
in accordance with Newton's second law of motion, lesser force acts on his hands and the 
player saves himself from being hurt.  
 
3.  
In fact friction is necessary evil. In case friction is not there, we cannot walk, we cannot 
travel in vehicles, we cannot light a match-stick, etc. Thus friction plays a very important 
role in our daily life.  
 
4. 
  
 
5.  
Angular momentum and linear momentum remain constant.  
 
6.  
Steel is more elastic than rubber, because the inter-atomic bonding strength is more in 
steel than that of rubber.  
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
7.  
Yes, during the change of state (such as melting of ice, boiling of water, etc.) the system 
absorbs heat but its temperature does not change. In this case, only the internal energy 
changes.  
 
8.  
  
 
9.  
The tip of the sharp pin is in the range of 10
-5
 to 10
-4
 m. The size of the nucleus is of the 
order of 10
-15
 to 10
-14
 m. Therefore, when the size of the nucleus is scaled up to the tip, we 
are scaling by a factor of 10
10
. Accordingly, the size of the atom will become 10
10
 x 10
-10
 = 1 
m.  
 
10.  
 
 
 
 
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
11. 
The resultant displacement due to 12 m towards east and 5 m towards north (which are at 
90
o
 to each other) lies in the plane of paper and is given by. 
  
Displacement 6 m is vertically upward perpendicular to the plane of paper. Therefore, the 
angle between R 1 and 6 m is 90º.The resultant of these to (say R 2) will be 
     
 
12.  
(i) Work done by the centripetal force is always zero. 
(ii)  When a person does not move from his position, but he may be holding any amount 
of load, the work done is zero. Similarly, when a coolie travels on a platform with some 
load on his head, work done by him is zero. 
 
13.  
(a) 6.67 × 10
-11
 Nm
2
kg
-2
 
(b) It is defined as the gravitational force of attraction between two bodies, each of 
mass 1 kg, separated by a distance of 1 m.  
 
14. 
(a) Pressure x Volume = Constant 
Or PV = Constant 
 
(b) Work done is 
 W = 2.3026 nRT log 10(V 2/V 1) 
 
Where R is the universal gas constant, n is the number of moles of gas, T is the absolute 
temperature,V 1 is the initial volume and V 2 is the final volume of the gas. 
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
OR 
We know that, PV RT ? 
We are given 
2
costant VP ?     
2
constant
RT
V
V
??
??
??
??
 
 
2
constant
T
V
?      
Using 
22
1
1
TT
VV
?       
We get, 
2
22
1
22
T
T V T
V
? ? ? 
 
1
2 TT ?      
 
15.  
 
 
 
 
 
 
 
 
 
 
  
 
CBSE  | Physics  
Sample Paper 7 Solution 
 
     
16.  
In the case of a closed organ pipe, one of the ends is open and the other is closed. In the 
case of a closed organ pipe, since one of the ends is open and the other is closed, the 
amplitude of vibrations of air particles is maximum at the open end and goes on decreasing 
till there is no vibration at the closed end. Therefore when the air column in a closed organ 
pipe vibrates in resonance, an antinode is formed at the open end and a node at the closed 
end. 
 
 
17.