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

## Class 11 : 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 90Âº.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

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 90Âº.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

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 90Âº.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

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.

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