Class 10 Science: CBSE (Official) Marking Scheme with Solution (2017-18) | Science Class 10 PDF Download

 Page 1


  Pg 1 of 7 
 
Marking Scheme 2017 – 18  
Science 
Class – X  
1 Hibiscus/Mustard  (or any other correct answer) 1 
2  
Pepsin Trypsin 
? Produced in stomach 
? Acts in acidic medium 
Produced by pancreas 
Acts in basic medium 
 
 
1 
(anyone) 
 
3 Atomic number of X = Mass number of X – No. of neutrons =35-18=17 
Electronic configuration = 2, 8, 7 
Group number = 17 , Period No. = 3 
½ 
½ 
½ 
½ 
4 
1.2 , 20 , 60
1 1 1
1 1 1
20 60
60
1.2 2.4
30
o
i
o
i
h cm f cm v cm
u f v
u
h v
hu
h x cm
? ? ? ? ?
??
??
??
?
?
?
? ? ? ?
?
 
 
 
½ 
 
 
½ 
 
 
½ 
 
½ 
 
5 i) Our demand for energy is increasing to improve quality of life and growth 
of population 
ii) Fossil fuels are limited                           (or any other two) 
1+1 
6 Electric generator 
Principle electormagenetic induction which states that electric current is 
induced in a closed circuit becaruse of changing magnetic field. 
 
OR 
i) Earth wire in electrical instruments saves us from all possible electric 
shocks. 
ii) Accidently, when live and neutral wires of an electric circuit comes into 
direct contact, it is called shor circuiting. 
iii) (a) 5A                    (b) 15A 
½ 
 
1 
 
 
1½ 
 
 
 
 
 
 
1+1+1  
 
7 
 
 
 
 
1 
 
 
Page 2


  Pg 1 of 7 
 
Marking Scheme 2017 – 18  
Science 
Class – X  
1 Hibiscus/Mustard  (or any other correct answer) 1 
2  
Pepsin Trypsin 
? Produced in stomach 
? Acts in acidic medium 
Produced by pancreas 
Acts in basic medium 
 
 
1 
(anyone) 
 
3 Atomic number of X = Mass number of X – No. of neutrons =35-18=17 
Electronic configuration = 2, 8, 7 
Group number = 17 , Period No. = 3 
½ 
½ 
½ 
½ 
4 
1.2 , 20 , 60
1 1 1
1 1 1
20 60
60
1.2 2.4
30
o
i
o
i
h cm f cm v cm
u f v
u
h v
hu
h x cm
? ? ? ? ?
??
??
??
?
?
?
? ? ? ?
?
 
 
 
½ 
 
 
½ 
 
 
½ 
 
½ 
 
5 i) Our demand for energy is increasing to improve quality of life and growth 
of population 
ii) Fossil fuels are limited                           (or any other two) 
1+1 
6 Electric generator 
Principle electormagenetic induction which states that electric current is 
induced in a closed circuit becaruse of changing magnetic field. 
 
OR 
i) Earth wire in electrical instruments saves us from all possible electric 
shocks. 
ii) Accidently, when live and neutral wires of an electric circuit comes into 
direct contact, it is called shor circuiting. 
iii) (a) 5A                    (b) 15A 
½ 
 
1 
 
 
1½ 
 
 
 
 
 
 
1+1+1  
 
7 
 
 
 
 
1 
 
 
  Pg 2 of 7 
Maximum current through 4 ? resister       
P
R
? 
                                                                  
16
2
4
A ??  
?Maximum current through each 8 ? resister 
1
21
2
xA ?? 
 
1 
 
 
 
 
1 
8 a) In the electrolysis of water, the gas collected at cathode is : Hydrogen 
                                                         The gas collected at anode is : oxygen 
b) The gas which is collected in double the amount during the 
electrolysis of water is Hydrogen. This is because water contains two 
parts of hydrogen element as compared to one part of oxygen 
element by volume. 
c) Pure water is a bad conductor of electricity, by adding drops of 
sulphuric acid; we make it a good conductor of electricity. 
1 
 
 
1 
 
 
1 
9  
 Mendeleev’s Periodic table Modern periodic table 
1. 
The elements were arranged 
according to increased atomic 
Masses.                                                              
The elements were arranged 
according to increased Atomic 
numbers. 
2. 
Position of isotopes was not 
Justified. 
There was no problem in the 
Placing of isotopes 
3. 
Position of hydrogen was not 
Justified because it resembles 
Both with Alkali metals and 
Halogens.                                 
Hydrogen has been given a 
unique position due to its 
resemblance with alkalis and 
Halogens. 
 
 
 
 
 
 
1 
 
1 
 
 
1 
 
10 There are two ways of anaerobic breakdown of glucose. First step is 
breakdown of glucose molecule into pyruvate which takes place in cytoplasm. 
 
The anaerobic breakdown in bacteria is called fermentation. During 
fermentation pyruvate is broken down to ethyl alcohol and carbondioxide. 
 
When there is lack of oxygen in our muscle cells pyruvate is broken down to 
lactic acid. 
Very less amount of energy is released in both the above cases.                 
1x3 
OR 
Arteries carry blood away from the heart while veins carry blood towards the 
heart. 
 
Arteries are thick walled while veins are thin walled. 
 
Valves are absent in arteries while valves are present in veins to ensure that 
blood flows in one direction only. (any other)  
(any three)     1x3 
3 
 
11 Mendel conducted a monohybrid cross with pea plants, and he observed that 
one of the contrasting characters disappears in F
1
 generator. This character 
reappears in F
2
 generation (obtained by selfing F
1
) in just 25% of the progeny. 
 
Mendel conclude that the character which epresses itself in F
1
 is the dominant 
½ x 6 
Page 3


  Pg 1 of 7 
 
Marking Scheme 2017 – 18  
Science 
Class – X  
1 Hibiscus/Mustard  (or any other correct answer) 1 
2  
Pepsin Trypsin 
? Produced in stomach 
? Acts in acidic medium 
Produced by pancreas 
Acts in basic medium 
 
 
1 
(anyone) 
 
3 Atomic number of X = Mass number of X – No. of neutrons =35-18=17 
Electronic configuration = 2, 8, 7 
Group number = 17 , Period No. = 3 
½ 
½ 
½ 
½ 
4 
1.2 , 20 , 60
1 1 1
1 1 1
20 60
60
1.2 2.4
30
o
i
o
i
h cm f cm v cm
u f v
u
h v
hu
h x cm
? ? ? ? ?
??
??
??
?
?
?
? ? ? ?
?
 
 
 
½ 
 
 
½ 
 
 
½ 
 
½ 
 
5 i) Our demand for energy is increasing to improve quality of life and growth 
of population 
ii) Fossil fuels are limited                           (or any other two) 
1+1 
6 Electric generator 
Principle electormagenetic induction which states that electric current is 
induced in a closed circuit becaruse of changing magnetic field. 
 
OR 
i) Earth wire in electrical instruments saves us from all possible electric 
shocks. 
ii) Accidently, when live and neutral wires of an electric circuit comes into 
direct contact, it is called shor circuiting. 
iii) (a) 5A                    (b) 15A 
½ 
 
1 
 
 
1½ 
 
 
 
 
 
 
1+1+1  
 
7 
 
 
 
 
1 
 
 
  Pg 2 of 7 
Maximum current through 4 ? resister       
P
R
? 
                                                                  
16
2
4
A ??  
?Maximum current through each 8 ? resister 
1
21
2
xA ?? 
 
1 
 
 
 
 
1 
8 a) In the electrolysis of water, the gas collected at cathode is : Hydrogen 
                                                         The gas collected at anode is : oxygen 
b) The gas which is collected in double the amount during the 
electrolysis of water is Hydrogen. This is because water contains two 
parts of hydrogen element as compared to one part of oxygen 
element by volume. 
c) Pure water is a bad conductor of electricity, by adding drops of 
sulphuric acid; we make it a good conductor of electricity. 
1 
 
 
1 
 
 
1 
9  
 Mendeleev’s Periodic table Modern periodic table 
1. 
The elements were arranged 
according to increased atomic 
Masses.                                                              
The elements were arranged 
according to increased Atomic 
numbers. 
2. 
Position of isotopes was not 
Justified. 
There was no problem in the 
Placing of isotopes 
3. 
Position of hydrogen was not 
Justified because it resembles 
Both with Alkali metals and 
Halogens.                                 
Hydrogen has been given a 
unique position due to its 
resemblance with alkalis and 
Halogens. 
 
 
 
 
 
 
1 
 
1 
 
 
1 
 
10 There are two ways of anaerobic breakdown of glucose. First step is 
breakdown of glucose molecule into pyruvate which takes place in cytoplasm. 
 
The anaerobic breakdown in bacteria is called fermentation. During 
fermentation pyruvate is broken down to ethyl alcohol and carbondioxide. 
 
When there is lack of oxygen in our muscle cells pyruvate is broken down to 
lactic acid. 
Very less amount of energy is released in both the above cases.                 
1x3 
OR 
Arteries carry blood away from the heart while veins carry blood towards the 
heart. 
 
Arteries are thick walled while veins are thin walled. 
 
Valves are absent in arteries while valves are present in veins to ensure that 
blood flows in one direction only. (any other)  
(any three)     1x3 
3 
 
11 Mendel conducted a monohybrid cross with pea plants, and he observed that 
one of the contrasting characters disappears in F
1
 generator. This character 
reappears in F
2
 generation (obtained by selfing F
1
) in just 25% of the progeny. 
 
Mendel conclude that the character which epresses itself in F
1
 is the dominant 
½ x 6 
  Pg 3 of 7 
character while the other one when is not able to epress thourhg present in F
1 
individuals is recessive. This recessive character is able to express only in its 
pure form i.e. in 25% of F
2 
individuals. 
 
 
12 i)  
50 26 24
74 50 24
2 24
24
12
2
u cm
v cm
f cm
f cm
? ? ?
? ? ?
??
? ? ?
 
ii)  
50 38 12 u cm ? ? ? 
i.e. Candle is at f 
?Image is formed at infinity. 
iii)  
 
 
 
1½ 
 
 
 
 
 
 
½ 
 
 
1 
13 Any three point given above –  
1. Plants and animals are pH sensitive. Living organisms can survive 
only in narrow range of pH change. 
2. pH of the soil. Plants require a specific pH range for their healthy 
growth. 
3. pH in our digestive system. Our stomach produces hydrochloric acid 
that helps in the digestion of food. During in digestion the stomach 
produces too much acid that cause pain and irritation. 
4. Change in pH causes tooth decay. Tooth decay start when the pH of 
the mouth is lower than 5.5. Tooth enamel gets corroded when the pH 
in the mouth is below 5.5. 
5. Self-defense by plants and animals through chemical warfare. Bee–
sting leaves and acid causing pain and irritation. Applying a mild base 
like baking soda on the stung area provides relief. 
OR 
The name of the compound is Plaster of Paris 
Its chemical formula is CaSO4. ½ H2O 
Equation: 
CaSO4.2H2O -------------> CaSO4. ½ H2O + 1 ½ H2O  
It is used in the hospitals mainly as plaster for supporting fractured bones in 
the right position 
1 + 1 + 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
½ 
½ 
 
1 
1 
14 Fossils provide evidence in favour of evoluation / establish evolutionary 
relationships by providing missing links. 
Two ways 
1. Relative method – Fossils found closer to the surface are more recent 
than those in deeper layer. 
2. By detecting the ratios of different isohpes of the same element in the 
fossils material.  
1 
 
 
1x2 
15 a) Viral / STD 1 
Page 4


  Pg 1 of 7 
 
Marking Scheme 2017 – 18  
Science 
Class – X  
1 Hibiscus/Mustard  (or any other correct answer) 1 
2  
Pepsin Trypsin 
? Produced in stomach 
? Acts in acidic medium 
Produced by pancreas 
Acts in basic medium 
 
 
1 
(anyone) 
 
3 Atomic number of X = Mass number of X – No. of neutrons =35-18=17 
Electronic configuration = 2, 8, 7 
Group number = 17 , Period No. = 3 
½ 
½ 
½ 
½ 
4 
1.2 , 20 , 60
1 1 1
1 1 1
20 60
60
1.2 2.4
30
o
i
o
i
h cm f cm v cm
u f v
u
h v
hu
h x cm
? ? ? ? ?
??
??
??
?
?
?
? ? ? ?
?
 
 
 
½ 
 
 
½ 
 
 
½ 
 
½ 
 
5 i) Our demand for energy is increasing to improve quality of life and growth 
of population 
ii) Fossil fuels are limited                           (or any other two) 
1+1 
6 Electric generator 
Principle electormagenetic induction which states that electric current is 
induced in a closed circuit becaruse of changing magnetic field. 
 
OR 
i) Earth wire in electrical instruments saves us from all possible electric 
shocks. 
ii) Accidently, when live and neutral wires of an electric circuit comes into 
direct contact, it is called shor circuiting. 
iii) (a) 5A                    (b) 15A 
½ 
 
1 
 
 
1½ 
 
 
 
 
 
 
1+1+1  
 
7 
 
 
 
 
1 
 
 
  Pg 2 of 7 
Maximum current through 4 ? resister       
P
R
? 
                                                                  
16
2
4
A ??  
?Maximum current through each 8 ? resister 
1
21
2
xA ?? 
 
1 
 
 
 
 
1 
8 a) In the electrolysis of water, the gas collected at cathode is : Hydrogen 
                                                         The gas collected at anode is : oxygen 
b) The gas which is collected in double the amount during the 
electrolysis of water is Hydrogen. This is because water contains two 
parts of hydrogen element as compared to one part of oxygen 
element by volume. 
c) Pure water is a bad conductor of electricity, by adding drops of 
sulphuric acid; we make it a good conductor of electricity. 
1 
 
 
1 
 
 
1 
9  
 Mendeleev’s Periodic table Modern periodic table 
1. 
The elements were arranged 
according to increased atomic 
Masses.                                                              
The elements were arranged 
according to increased Atomic 
numbers. 
2. 
Position of isotopes was not 
Justified. 
There was no problem in the 
Placing of isotopes 
3. 
Position of hydrogen was not 
Justified because it resembles 
Both with Alkali metals and 
Halogens.                                 
Hydrogen has been given a 
unique position due to its 
resemblance with alkalis and 
Halogens. 
 
 
 
 
 
 
1 
 
1 
 
 
1 
 
10 There are two ways of anaerobic breakdown of glucose. First step is 
breakdown of glucose molecule into pyruvate which takes place in cytoplasm. 
 
The anaerobic breakdown in bacteria is called fermentation. During 
fermentation pyruvate is broken down to ethyl alcohol and carbondioxide. 
 
When there is lack of oxygen in our muscle cells pyruvate is broken down to 
lactic acid. 
Very less amount of energy is released in both the above cases.                 
1x3 
OR 
Arteries carry blood away from the heart while veins carry blood towards the 
heart. 
 
Arteries are thick walled while veins are thin walled. 
 
Valves are absent in arteries while valves are present in veins to ensure that 
blood flows in one direction only. (any other)  
(any three)     1x3 
3 
 
11 Mendel conducted a monohybrid cross with pea plants, and he observed that 
one of the contrasting characters disappears in F
1
 generator. This character 
reappears in F
2
 generation (obtained by selfing F
1
) in just 25% of the progeny. 
 
Mendel conclude that the character which epresses itself in F
1
 is the dominant 
½ x 6 
  Pg 3 of 7 
character while the other one when is not able to epress thourhg present in F
1 
individuals is recessive. This recessive character is able to express only in its 
pure form i.e. in 25% of F
2 
individuals. 
 
 
12 i)  
50 26 24
74 50 24
2 24
24
12
2
u cm
v cm
f cm
f cm
? ? ?
? ? ?
??
? ? ?
 
ii)  
50 38 12 u cm ? ? ? 
i.e. Candle is at f 
?Image is formed at infinity. 
iii)  
 
 
 
1½ 
 
 
 
 
 
 
½ 
 
 
1 
13 Any three point given above –  
1. Plants and animals are pH sensitive. Living organisms can survive 
only in narrow range of pH change. 
2. pH of the soil. Plants require a specific pH range for their healthy 
growth. 
3. pH in our digestive system. Our stomach produces hydrochloric acid 
that helps in the digestion of food. During in digestion the stomach 
produces too much acid that cause pain and irritation. 
4. Change in pH causes tooth decay. Tooth decay start when the pH of 
the mouth is lower than 5.5. Tooth enamel gets corroded when the pH 
in the mouth is below 5.5. 
5. Self-defense by plants and animals through chemical warfare. Bee–
sting leaves and acid causing pain and irritation. Applying a mild base 
like baking soda on the stung area provides relief. 
OR 
The name of the compound is Plaster of Paris 
Its chemical formula is CaSO4. ½ H2O 
Equation: 
CaSO4.2H2O -------------> CaSO4. ½ H2O + 1 ½ H2O  
It is used in the hospitals mainly as plaster for supporting fractured bones in 
the right position 
1 + 1 + 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
½ 
½ 
 
1 
1 
14 Fossils provide evidence in favour of evoluation / establish evolutionary 
relationships by providing missing links. 
Two ways 
1. Relative method – Fossils found closer to the surface are more recent 
than those in deeper layer. 
2. By detecting the ratios of different isohpes of the same element in the 
fossils material.  
1 
 
 
1x2 
15 a) Viral / STD 1 
  Pg 4 of 7 
HIV 
b) Senstivity and awareness among the citizens towards leading a 
healthy and fit life. 
1 
1 
16 Activity (Refer circuit diagram given below) 
Take a battery (12 V), a variable resistance (or a rheostat), an ammeter (0–5 
A), a plug key, and a long straight thick copper wire. Insert the thick wire 
through the centre, normal to the plane of a rectangular cardboard. Take care 
that the cardboard is fixed and does not slide up or down. Connect the 
copper wire vertically between the points X and Y, as shown in diagram in 
series with the battery, a plug and key. Sprinkle some iron filings uniformly on 
the cardboard. Keep the variable of the rheostat at a fixed position and note 
the current through the ammeter. Close the key so that a current flows 
through the wire. Ensure that the copper wire placed between the points X 
and Y remains vertically straight. Gently tap the cardboard a few times. 
Observe the pattern of the iron filings. It is observed that the iron filings align 
themselves showing a pattern of concentric circles around the copper wire. 
These represent the magnetic field lines.  
 
 
i) Right hand thumb rule 
ii) Yes, Alpha particles being, positively charged constitues a current in 
the direction of motion. 
No, Neutron being electrically neutral consitiute no current. 
2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1 
 
 
 
 
 
 
2 
17 
OR 
 
1+1+1+1+1 
 
 
 
 
 
 
 
 
 
 
 
 
1½+1 
 
 
 
 
 
 
1½+1 
Page 5


  Pg 1 of 7 
 
Marking Scheme 2017 – 18  
Science 
Class – X  
1 Hibiscus/Mustard  (or any other correct answer) 1 
2  
Pepsin Trypsin 
? Produced in stomach 
? Acts in acidic medium 
Produced by pancreas 
Acts in basic medium 
 
 
1 
(anyone) 
 
3 Atomic number of X = Mass number of X – No. of neutrons =35-18=17 
Electronic configuration = 2, 8, 7 
Group number = 17 , Period No. = 3 
½ 
½ 
½ 
½ 
4 
1.2 , 20 , 60
1 1 1
1 1 1
20 60
60
1.2 2.4
30
o
i
o
i
h cm f cm v cm
u f v
u
h v
hu
h x cm
? ? ? ? ?
??
??
??
?
?
?
? ? ? ?
?
 
 
 
½ 
 
 
½ 
 
 
½ 
 
½ 
 
5 i) Our demand for energy is increasing to improve quality of life and growth 
of population 
ii) Fossil fuels are limited                           (or any other two) 
1+1 
6 Electric generator 
Principle electormagenetic induction which states that electric current is 
induced in a closed circuit becaruse of changing magnetic field. 
 
OR 
i) Earth wire in electrical instruments saves us from all possible electric 
shocks. 
ii) Accidently, when live and neutral wires of an electric circuit comes into 
direct contact, it is called shor circuiting. 
iii) (a) 5A                    (b) 15A 
½ 
 
1 
 
 
1½ 
 
 
 
 
 
 
1+1+1  
 
7 
 
 
 
 
1 
 
 
  Pg 2 of 7 
Maximum current through 4 ? resister       
P
R
? 
                                                                  
16
2
4
A ??  
?Maximum current through each 8 ? resister 
1
21
2
xA ?? 
 
1 
 
 
 
 
1 
8 a) In the electrolysis of water, the gas collected at cathode is : Hydrogen 
                                                         The gas collected at anode is : oxygen 
b) The gas which is collected in double the amount during the 
electrolysis of water is Hydrogen. This is because water contains two 
parts of hydrogen element as compared to one part of oxygen 
element by volume. 
c) Pure water is a bad conductor of electricity, by adding drops of 
sulphuric acid; we make it a good conductor of electricity. 
1 
 
 
1 
 
 
1 
9  
 Mendeleev’s Periodic table Modern periodic table 
1. 
The elements were arranged 
according to increased atomic 
Masses.                                                              
The elements were arranged 
according to increased Atomic 
numbers. 
2. 
Position of isotopes was not 
Justified. 
There was no problem in the 
Placing of isotopes 
3. 
Position of hydrogen was not 
Justified because it resembles 
Both with Alkali metals and 
Halogens.                                 
Hydrogen has been given a 
unique position due to its 
resemblance with alkalis and 
Halogens. 
 
 
 
 
 
 
1 
 
1 
 
 
1 
 
10 There are two ways of anaerobic breakdown of glucose. First step is 
breakdown of glucose molecule into pyruvate which takes place in cytoplasm. 
 
The anaerobic breakdown in bacteria is called fermentation. During 
fermentation pyruvate is broken down to ethyl alcohol and carbondioxide. 
 
When there is lack of oxygen in our muscle cells pyruvate is broken down to 
lactic acid. 
Very less amount of energy is released in both the above cases.                 
1x3 
OR 
Arteries carry blood away from the heart while veins carry blood towards the 
heart. 
 
Arteries are thick walled while veins are thin walled. 
 
Valves are absent in arteries while valves are present in veins to ensure that 
blood flows in one direction only. (any other)  
(any three)     1x3 
3 
 
11 Mendel conducted a monohybrid cross with pea plants, and he observed that 
one of the contrasting characters disappears in F
1
 generator. This character 
reappears in F
2
 generation (obtained by selfing F
1
) in just 25% of the progeny. 
 
Mendel conclude that the character which epresses itself in F
1
 is the dominant 
½ x 6 
  Pg 3 of 7 
character while the other one when is not able to epress thourhg present in F
1 
individuals is recessive. This recessive character is able to express only in its 
pure form i.e. in 25% of F
2 
individuals. 
 
 
12 i)  
50 26 24
74 50 24
2 24
24
12
2
u cm
v cm
f cm
f cm
? ? ?
? ? ?
??
? ? ?
 
ii)  
50 38 12 u cm ? ? ? 
i.e. Candle is at f 
?Image is formed at infinity. 
iii)  
 
 
 
1½ 
 
 
 
 
 
 
½ 
 
 
1 
13 Any three point given above –  
1. Plants and animals are pH sensitive. Living organisms can survive 
only in narrow range of pH change. 
2. pH of the soil. Plants require a specific pH range for their healthy 
growth. 
3. pH in our digestive system. Our stomach produces hydrochloric acid 
that helps in the digestion of food. During in digestion the stomach 
produces too much acid that cause pain and irritation. 
4. Change in pH causes tooth decay. Tooth decay start when the pH of 
the mouth is lower than 5.5. Tooth enamel gets corroded when the pH 
in the mouth is below 5.5. 
5. Self-defense by plants and animals through chemical warfare. Bee–
sting leaves and acid causing pain and irritation. Applying a mild base 
like baking soda on the stung area provides relief. 
OR 
The name of the compound is Plaster of Paris 
Its chemical formula is CaSO4. ½ H2O 
Equation: 
CaSO4.2H2O -------------> CaSO4. ½ H2O + 1 ½ H2O  
It is used in the hospitals mainly as plaster for supporting fractured bones in 
the right position 
1 + 1 + 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
½ 
½ 
 
1 
1 
14 Fossils provide evidence in favour of evoluation / establish evolutionary 
relationships by providing missing links. 
Two ways 
1. Relative method – Fossils found closer to the surface are more recent 
than those in deeper layer. 
2. By detecting the ratios of different isohpes of the same element in the 
fossils material.  
1 
 
 
1x2 
15 a) Viral / STD 1 
  Pg 4 of 7 
HIV 
b) Senstivity and awareness among the citizens towards leading a 
healthy and fit life. 
1 
1 
16 Activity (Refer circuit diagram given below) 
Take a battery (12 V), a variable resistance (or a rheostat), an ammeter (0–5 
A), a plug key, and a long straight thick copper wire. Insert the thick wire 
through the centre, normal to the plane of a rectangular cardboard. Take care 
that the cardboard is fixed and does not slide up or down. Connect the 
copper wire vertically between the points X and Y, as shown in diagram in 
series with the battery, a plug and key. Sprinkle some iron filings uniformly on 
the cardboard. Keep the variable of the rheostat at a fixed position and note 
the current through the ammeter. Close the key so that a current flows 
through the wire. Ensure that the copper wire placed between the points X 
and Y remains vertically straight. Gently tap the cardboard a few times. 
Observe the pattern of the iron filings. It is observed that the iron filings align 
themselves showing a pattern of concentric circles around the copper wire. 
These represent the magnetic field lines.  
 
 
i) Right hand thumb rule 
ii) Yes, Alpha particles being, positively charged constitues a current in 
the direction of motion. 
No, Neutron being electrically neutral consitiute no current. 
2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1 
 
 
 
 
 
 
2 
17 
OR 
 
1+1+1+1+1 
 
 
 
 
 
 
 
 
 
 
 
 
1½+1 
 
 
 
 
 
 
1½+1 
  Pg 5 of 7 
 
18 a)  
i)  
  
 
ii) Correct labelling 
iii) Medulla controls blood pressure, salivation x vomiting 
Cerebellum controls precision of voluntary movements and 
equilibrium. 
(any one function each of Medulla and Cerebellum) 
b) Over production of growth hormone leads to gigantism and it’s 
underproduction leads to dwarfism 
 
 
 
 
 
2 
 
 
 
 
 
 
 
 
1 
½+ ½ 
 
1 
19 a) Myopia 
b)  
1
0.22
45
f cm
?
? ? ? 
Concave lens 
c)  
 
d) Causes – i) Due to excess curvature of eye lens 
iii) Elongation of the eye ball. 
 
1 
 
½+ ½ 
 
 
 
 
 
1+1 
 
 
 
 
 
 
½+ ½ 
 
20 a) The arrangement of metals in the vertical column in the order of 
decreasing reactivity is called reactivity series or activity series.  
A metal placed above hydrogen in the activity series will displace 
5