Class 9 Science: Solutions of Sample Practice Question Paper- 3 PDF Download

 Page 1


  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
CBSE  
Class IX Science 
Sample Paper – 3 Solution  
                                                                                                                           
Section A 
 
1. Processes which play an important role in the oxygen cycle: 
(a) Photosynthesis  
(b) Respiration 
 
2. Some useful traits in improved crops: 
(a) Higher yield 
(b) Resistance to biotic and abiotic stresses 
 
  Section B 
 
3. A change of state of a substance directly from solid to gas without changing to a 
liquid state (or vice versa) is called sublimation. 
The common substances which undergo sublimation are camphor, naphthalene, 
ammonium chloride and iodine. 
OR 
The random motion of particles suspended in a fluid (liquid or gas) results from the 
bombardment by fast-moving atoms or molecules in the fluid (liquid or gas). This 
haphazard motion of particles is known as Brownian motion. 
 
 
4. Methods used for reducing reverberation in a large hall or auditorium: 
(i) Panels made of sound-absorbing material can be put up on the walls and the 
ceiling of the hall or auditorium. 
(ii) Carpets can be put on the floor to absorb sound. 
(iii) Heavy curtains can be put up on doors and windows to absorb sound. 
(iv) Seats can be made of materials having sound-absorbing capabilities. 
 
  
Page 2


  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
CBSE  
Class IX Science 
Sample Paper – 3 Solution  
                                                                                                                           
Section A 
 
1. Processes which play an important role in the oxygen cycle: 
(a) Photosynthesis  
(b) Respiration 
 
2. Some useful traits in improved crops: 
(a) Higher yield 
(b) Resistance to biotic and abiotic stresses 
 
  Section B 
 
3. A change of state of a substance directly from solid to gas without changing to a 
liquid state (or vice versa) is called sublimation. 
The common substances which undergo sublimation are camphor, naphthalene, 
ammonium chloride and iodine. 
OR 
The random motion of particles suspended in a fluid (liquid or gas) results from the 
bombardment by fast-moving atoms or molecules in the fluid (liquid or gas). This 
haphazard motion of particles is known as Brownian motion. 
 
 
4. Methods used for reducing reverberation in a large hall or auditorium: 
(i) Panels made of sound-absorbing material can be put up on the walls and the 
ceiling of the hall or auditorium. 
(ii) Carpets can be put on the floor to absorb sound. 
(iii) Heavy curtains can be put up on doors and windows to absorb sound. 
(iv) Seats can be made of materials having sound-absorbing capabilities. 
 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
5. P – Vacuole; Q – Mitochondria 
(a) Vacuoles help maintain the osmotic pressure in a cell. They store toxic 
metabolic by-products of plant cells. They also provide turgidity and rigidity to 
plant cells. 
(b) Mitochondria synthesise energy-rich compounds (ATP) for the cell. In the 
absence of mitochondria, the cell will not have energy to carry out important 
life processes such as photosynthesis, respiration and protein synthesis. 
 
 
Section C 
6.  
(a) Speed is the distance travelled by a body per unit time. Its SI unit is metre per 
second (m/s). 
Distance m
Speed
Time s
??
 
(b)  
(i) The average speed of a body is the total distance travelled divided by the 
total time taken to cover that distance. 
(ii) Uniform speed is the speed of a body if it travels equal distances in equal 
intervals of time. 
 
(c) Speed of a body tells us how fast a body is travelling, but velocity not only tells us 
how fast the body is travelling but also gives us the direction in which the body 
is travelling. 
 
7. (a) General characters of Phylum Mollusca: 
(i) Body is soft, bilaterally symmetrical and without appendages. 
(ii) Body is divisible into the anterior head, a ventral muscular foot and a hard 
dorsal visceral mass. The entire body is covered by a fold of thin skin called 
mantle. 
(iii) Respiration occurs through the gills or lungs of the mantle. 
(iv) Excretion occurs by a pair of metanephridia or kidneys. 
(b) Examples: Snail, octopus 
 
  
Page 3


  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
CBSE  
Class IX Science 
Sample Paper – 3 Solution  
                                                                                                                           
Section A 
 
1. Processes which play an important role in the oxygen cycle: 
(a) Photosynthesis  
(b) Respiration 
 
2. Some useful traits in improved crops: 
(a) Higher yield 
(b) Resistance to biotic and abiotic stresses 
 
  Section B 
 
3. A change of state of a substance directly from solid to gas without changing to a 
liquid state (or vice versa) is called sublimation. 
The common substances which undergo sublimation are camphor, naphthalene, 
ammonium chloride and iodine. 
OR 
The random motion of particles suspended in a fluid (liquid or gas) results from the 
bombardment by fast-moving atoms or molecules in the fluid (liquid or gas). This 
haphazard motion of particles is known as Brownian motion. 
 
 
4. Methods used for reducing reverberation in a large hall or auditorium: 
(i) Panels made of sound-absorbing material can be put up on the walls and the 
ceiling of the hall or auditorium. 
(ii) Carpets can be put on the floor to absorb sound. 
(iii) Heavy curtains can be put up on doors and windows to absorb sound. 
(iv) Seats can be made of materials having sound-absorbing capabilities. 
 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
5. P – Vacuole; Q – Mitochondria 
(a) Vacuoles help maintain the osmotic pressure in a cell. They store toxic 
metabolic by-products of plant cells. They also provide turgidity and rigidity to 
plant cells. 
(b) Mitochondria synthesise energy-rich compounds (ATP) for the cell. In the 
absence of mitochondria, the cell will not have energy to carry out important 
life processes such as photosynthesis, respiration and protein synthesis. 
 
 
Section C 
6.  
(a) Speed is the distance travelled by a body per unit time. Its SI unit is metre per 
second (m/s). 
Distance m
Speed
Time s
??
 
(b)  
(i) The average speed of a body is the total distance travelled divided by the 
total time taken to cover that distance. 
(ii) Uniform speed is the speed of a body if it travels equal distances in equal 
intervals of time. 
 
(c) Speed of a body tells us how fast a body is travelling, but velocity not only tells us 
how fast the body is travelling but also gives us the direction in which the body 
is travelling. 
 
7. (a) General characters of Phylum Mollusca: 
(i) Body is soft, bilaterally symmetrical and without appendages. 
(ii) Body is divisible into the anterior head, a ventral muscular foot and a hard 
dorsal visceral mass. The entire body is covered by a fold of thin skin called 
mantle. 
(iii) Respiration occurs through the gills or lungs of the mantle. 
(iv) Excretion occurs by a pair of metanephridia or kidneys. 
(b) Examples: Snail, octopus 
 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
8.  
(a) When a person jumps out of a moving bus, he has high speed and will tend to 
continue his state of motion. Because of this, there is a possibility of injury by 
falling on the ground. Hence, jumping from a moving bus is dangerous. 
 
(b) A fast-moving cricket ball has large momentum. While catching this ball, its 
momentum is reduced to zero. When a cricketer catches the ball, the impact can 
injure his hands. To prevent this, he takes his hands backwards. This increases 
the time taken to reduce the momentum to zero thereby decreasing the rate of 
change of momentum. Hence, a smaller force acts on the hands thereby 
preventing injury. 
 
9. Given: 
Mass of boron = 0.096 g 
Mass of oxygen = 0.144 g 
Mass of the sample compound (boron + oxygen) = 0.24 g 
According to the law of definite proportions, boron and oxygen are in a fixed ratio in 
the given compound = 0.096:0.144 = 2:3 
mass of boron  100 0.096  100
% of boron 40%
mass of compound 0.24
mass oxygen 100 0.144 100
% of oxygen 60%
mass of compound 0.24
??
? ? ?
??
? ? ?
 
 
10.  
(a) The child must have been infected through contaminated water, food, drinks, 
hands, clothes or utensils leading to diarrhoea. 
(b) Before being taken to the doctor, the child can be given oral rehydration solution 
(ORS) to restore the amount of fluids in the body and prevent dehydration.  
(c) Compassion, kindness, responsible behaviour and caring attitude are some of 
the values depicted by Sarla. 
 
11. Mass of the bullet, m = 20 g 
20
m 0.02 kg
1000
?? 
Initial speed of the bullet, u1 = 400 m/s 
Mass of the target, M = 1.5 kg 
Initial speed of the target, u2 = 0 m/s 
The bullet gets embedded in the target. So, the total mass of the bullet and the target 
becomes 
M' = m + M = 1.52 kg 
Both objects move together with speed v2. 
  
Page 4


  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
CBSE  
Class IX Science 
Sample Paper – 3 Solution  
                                                                                                                           
Section A 
 
1. Processes which play an important role in the oxygen cycle: 
(a) Photosynthesis  
(b) Respiration 
 
2. Some useful traits in improved crops: 
(a) Higher yield 
(b) Resistance to biotic and abiotic stresses 
 
  Section B 
 
3. A change of state of a substance directly from solid to gas without changing to a 
liquid state (or vice versa) is called sublimation. 
The common substances which undergo sublimation are camphor, naphthalene, 
ammonium chloride and iodine. 
OR 
The random motion of particles suspended in a fluid (liquid or gas) results from the 
bombardment by fast-moving atoms or molecules in the fluid (liquid or gas). This 
haphazard motion of particles is known as Brownian motion. 
 
 
4. Methods used for reducing reverberation in a large hall or auditorium: 
(i) Panels made of sound-absorbing material can be put up on the walls and the 
ceiling of the hall or auditorium. 
(ii) Carpets can be put on the floor to absorb sound. 
(iii) Heavy curtains can be put up on doors and windows to absorb sound. 
(iv) Seats can be made of materials having sound-absorbing capabilities. 
 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
5. P – Vacuole; Q – Mitochondria 
(a) Vacuoles help maintain the osmotic pressure in a cell. They store toxic 
metabolic by-products of plant cells. They also provide turgidity and rigidity to 
plant cells. 
(b) Mitochondria synthesise energy-rich compounds (ATP) for the cell. In the 
absence of mitochondria, the cell will not have energy to carry out important 
life processes such as photosynthesis, respiration and protein synthesis. 
 
 
Section C 
6.  
(a) Speed is the distance travelled by a body per unit time. Its SI unit is metre per 
second (m/s). 
Distance m
Speed
Time s
??
 
(b)  
(i) The average speed of a body is the total distance travelled divided by the 
total time taken to cover that distance. 
(ii) Uniform speed is the speed of a body if it travels equal distances in equal 
intervals of time. 
 
(c) Speed of a body tells us how fast a body is travelling, but velocity not only tells us 
how fast the body is travelling but also gives us the direction in which the body 
is travelling. 
 
7. (a) General characters of Phylum Mollusca: 
(i) Body is soft, bilaterally symmetrical and without appendages. 
(ii) Body is divisible into the anterior head, a ventral muscular foot and a hard 
dorsal visceral mass. The entire body is covered by a fold of thin skin called 
mantle. 
(iii) Respiration occurs through the gills or lungs of the mantle. 
(iv) Excretion occurs by a pair of metanephridia or kidneys. 
(b) Examples: Snail, octopus 
 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
8.  
(a) When a person jumps out of a moving bus, he has high speed and will tend to 
continue his state of motion. Because of this, there is a possibility of injury by 
falling on the ground. Hence, jumping from a moving bus is dangerous. 
 
(b) A fast-moving cricket ball has large momentum. While catching this ball, its 
momentum is reduced to zero. When a cricketer catches the ball, the impact can 
injure his hands. To prevent this, he takes his hands backwards. This increases 
the time taken to reduce the momentum to zero thereby decreasing the rate of 
change of momentum. Hence, a smaller force acts on the hands thereby 
preventing injury. 
 
9. Given: 
Mass of boron = 0.096 g 
Mass of oxygen = 0.144 g 
Mass of the sample compound (boron + oxygen) = 0.24 g 
According to the law of definite proportions, boron and oxygen are in a fixed ratio in 
the given compound = 0.096:0.144 = 2:3 
mass of boron  100 0.096  100
% of boron 40%
mass of compound 0.24
mass oxygen 100 0.144 100
% of oxygen 60%
mass of compound 0.24
??
? ? ?
??
? ? ?
 
 
10.  
(a) The child must have been infected through contaminated water, food, drinks, 
hands, clothes or utensils leading to diarrhoea. 
(b) Before being taken to the doctor, the child can be given oral rehydration solution 
(ORS) to restore the amount of fluids in the body and prevent dehydration.  
(c) Compassion, kindness, responsible behaviour and caring attitude are some of 
the values depicted by Sarla. 
 
11. Mass of the bullet, m = 20 g 
20
m 0.02 kg
1000
?? 
Initial speed of the bullet, u1 = 400 m/s 
Mass of the target, M = 1.5 kg 
Initial speed of the target, u2 = 0 m/s 
The bullet gets embedded in the target. So, the total mass of the bullet and the target 
becomes 
M' = m + M = 1.52 kg 
Both objects move together with speed v2. 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
According to the law of conservation of linear momentum, 
1 1 2 2 2
1 1 2
11
2
2
m u m u M'v
m u M'v
mu 0.02 400
v
M' 1.52
v 5.26 m/s
??
??
?
? ? ?
??
 
OR 
 
 
 
(a) Acceleration between points A and B will be given by the slope of line AB. 
BA
AB
BA
2
AB
vv
Slope a
tt
40 20 20
a 6.67 m/s
3 0 3
?
??
?
?
? ? ? ?
?
 
(b) Velocity of the body is constant between points B and C. Hence, the acceleration 
will be zero. So, aBC = 0 
(c) Acceleration between points C and D will be given by the slope of line CD. 
DC
CD
DC
2
CD
vv
Slope a
tt
0 40 40
a 20 m/s
8 6 2
?
??
?
??
? ? ? ? ?
?
 
 
12.  
(a) The field shows intercropping of sunflower and groundnut crops. 
(b) Advantages of intercropping: 
(i) It increases the productivity of crops per unit area. 
(ii) It helps maintain soil fertility and allows better use of natural resources.  
OR 
 
Page 5


  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
CBSE  
Class IX Science 
Sample Paper – 3 Solution  
                                                                                                                           
Section A 
 
1. Processes which play an important role in the oxygen cycle: 
(a) Photosynthesis  
(b) Respiration 
 
2. Some useful traits in improved crops: 
(a) Higher yield 
(b) Resistance to biotic and abiotic stresses 
 
  Section B 
 
3. A change of state of a substance directly from solid to gas without changing to a 
liquid state (or vice versa) is called sublimation. 
The common substances which undergo sublimation are camphor, naphthalene, 
ammonium chloride and iodine. 
OR 
The random motion of particles suspended in a fluid (liquid or gas) results from the 
bombardment by fast-moving atoms or molecules in the fluid (liquid or gas). This 
haphazard motion of particles is known as Brownian motion. 
 
 
4. Methods used for reducing reverberation in a large hall or auditorium: 
(i) Panels made of sound-absorbing material can be put up on the walls and the 
ceiling of the hall or auditorium. 
(ii) Carpets can be put on the floor to absorb sound. 
(iii) Heavy curtains can be put up on doors and windows to absorb sound. 
(iv) Seats can be made of materials having sound-absorbing capabilities. 
 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
5. P – Vacuole; Q – Mitochondria 
(a) Vacuoles help maintain the osmotic pressure in a cell. They store toxic 
metabolic by-products of plant cells. They also provide turgidity and rigidity to 
plant cells. 
(b) Mitochondria synthesise energy-rich compounds (ATP) for the cell. In the 
absence of mitochondria, the cell will not have energy to carry out important 
life processes such as photosynthesis, respiration and protein synthesis. 
 
 
Section C 
6.  
(a) Speed is the distance travelled by a body per unit time. Its SI unit is metre per 
second (m/s). 
Distance m
Speed
Time s
??
 
(b)  
(i) The average speed of a body is the total distance travelled divided by the 
total time taken to cover that distance. 
(ii) Uniform speed is the speed of a body if it travels equal distances in equal 
intervals of time. 
 
(c) Speed of a body tells us how fast a body is travelling, but velocity not only tells us 
how fast the body is travelling but also gives us the direction in which the body 
is travelling. 
 
7. (a) General characters of Phylum Mollusca: 
(i) Body is soft, bilaterally symmetrical and without appendages. 
(ii) Body is divisible into the anterior head, a ventral muscular foot and a hard 
dorsal visceral mass. The entire body is covered by a fold of thin skin called 
mantle. 
(iii) Respiration occurs through the gills or lungs of the mantle. 
(iv) Excretion occurs by a pair of metanephridia or kidneys. 
(b) Examples: Snail, octopus 
 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
8.  
(a) When a person jumps out of a moving bus, he has high speed and will tend to 
continue his state of motion. Because of this, there is a possibility of injury by 
falling on the ground. Hence, jumping from a moving bus is dangerous. 
 
(b) A fast-moving cricket ball has large momentum. While catching this ball, its 
momentum is reduced to zero. When a cricketer catches the ball, the impact can 
injure his hands. To prevent this, he takes his hands backwards. This increases 
the time taken to reduce the momentum to zero thereby decreasing the rate of 
change of momentum. Hence, a smaller force acts on the hands thereby 
preventing injury. 
 
9. Given: 
Mass of boron = 0.096 g 
Mass of oxygen = 0.144 g 
Mass of the sample compound (boron + oxygen) = 0.24 g 
According to the law of definite proportions, boron and oxygen are in a fixed ratio in 
the given compound = 0.096:0.144 = 2:3 
mass of boron  100 0.096  100
% of boron 40%
mass of compound 0.24
mass oxygen 100 0.144 100
% of oxygen 60%
mass of compound 0.24
??
? ? ?
??
? ? ?
 
 
10.  
(a) The child must have been infected through contaminated water, food, drinks, 
hands, clothes or utensils leading to diarrhoea. 
(b) Before being taken to the doctor, the child can be given oral rehydration solution 
(ORS) to restore the amount of fluids in the body and prevent dehydration.  
(c) Compassion, kindness, responsible behaviour and caring attitude are some of 
the values depicted by Sarla. 
 
11. Mass of the bullet, m = 20 g 
20
m 0.02 kg
1000
?? 
Initial speed of the bullet, u1 = 400 m/s 
Mass of the target, M = 1.5 kg 
Initial speed of the target, u2 = 0 m/s 
The bullet gets embedded in the target. So, the total mass of the bullet and the target 
becomes 
M' = m + M = 1.52 kg 
Both objects move together with speed v2. 
  
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
According to the law of conservation of linear momentum, 
1 1 2 2 2
1 1 2
11
2
2
m u m u M'v
m u M'v
mu 0.02 400
v
M' 1.52
v 5.26 m/s
??
??
?
? ? ?
??
 
OR 
 
 
 
(a) Acceleration between points A and B will be given by the slope of line AB. 
BA
AB
BA
2
AB
vv
Slope a
tt
40 20 20
a 6.67 m/s
3 0 3
?
??
?
?
? ? ? ?
?
 
(b) Velocity of the body is constant between points B and C. Hence, the acceleration 
will be zero. So, aBC = 0 
(c) Acceleration between points C and D will be given by the slope of line CD. 
DC
CD
DC
2
CD
vv
Slope a
tt
0 40 40
a 20 m/s
8 6 2
?
??
?
??
? ? ? ? ?
?
 
 
12.  
(a) The field shows intercropping of sunflower and groundnut crops. 
(b) Advantages of intercropping: 
(i) It increases the productivity of crops per unit area. 
(ii) It helps maintain soil fertility and allows better use of natural resources.  
OR 
 
  
 
CBSE IX | SCIENCE 
 Sample Paper – 3 Solution 
 
     
(a) To obtain the maximum benefit from a crop field, we should adopt the following 
practices: 
(i) Maintain soil fertility through judicious use of manures and fertilisers 
(ii) Practise crop rotation 
(iii) Employ cropping patterns such as mixed cropping and intercropping 
(iv) Keep a check on the weed and insect pest population 
(b) The pea crop would require a minimum quantity of fertilisers for its proper 
growth because pea is a dicot leguminous plant. The root nodules of leguminous 
plants contain nitrogen fixing bacteria which supply essential nutrients required 
for plant growth. 
 
13.  
(a) Valence electrons of an element determine the chemical properties of an 
element. Valence electrons have maximum energy, and hence, when they come 
close to the valence electrons of some other element, they either get transferred 
or shared. 
(b) Electrons in the shell other than the valence shell do not get transferred or 
shared and hence do not determine the chemical properties of elements. 
OR 
(a) For element A, Z = 11 
Electronic configuration = (2, 8, 1) 
Valency = 1 
For element B, Z = 13 
Electronic configuration = (2, 8, 3) 
Valency = 3 
Element A is Sodium (Na). 
Element B is Aluminium (Al). 
 
(b) Atoms of the same element differing in the number of neutrons in their nuclei are 
known as isotopes. Thus, isotopes of an element have the same atomic number 
but different atomic mass numbers. 
Example: 
Isotopes of hydrogen: Protium (
1
H
1
) 
                                           Deuterium (
2
H
1
) 
                                           Tritium (
3
H
1
) 
 
 
14. Yes, we can turn liquid into vapour without heating. Vaporisation of water during 
evaporation occurs below the boiling point under atmospheric pressure.