Class 10 Science: CBSE (Official) Sample Question Paper (2023-24) | CBSE Sample Papers For Class 10 PDF Download

 Page 1


1 
 
 
Sample Question Paper 2023-24 
Class X  
Science (Subject Code – 086)  
 
Max. Marks: 80 Time Allowed: 3 hours 
General Instructions: 
i. This question paper consists of 39 questions in 5 sections. 
ii. All questions are compulsory. However, an internal choice is provided in some questions. A student is 
expected to attempt only one of these questions. 
iii. Section A consists of 20 objective type questions carrying 1 mark each. 
iv. Section B consists of 6 Very Short questions carrying 02 marks each. Answers to these questions 
should be in the range of 30 to 50 words. 
v. Section C consists of 7 Short Answer type questions carrying 03 marks each. Answers to these 
questions should be in the range of 50 to 80 words. 
vi. Section D consists of 3 Long Answer type questions carrying 05 marks each. Answer to these 
questions should be in the range of 80 to 120 words. 
vii. Section E consists of 3 source-based/case-based units of assessment of 04 marks each with sub-parts. 
Section-A 
Select and write the most appropriate option out of the four options given for each 
 of the questions 1 - 20. There is no negative mark for incorrect response. 
Q. Nos. Questions Marks 
1 
 
Identify the product which represents the solid state in the above reaction. 
a) Barium chloride 
b) Barium sulphate 
c) Sodium chloride 
d) Sodium sulphate 
1 
2 
The colour of the solution observed after 30 minutes of placing zinc metal to copper 
sulphate solution is 
a) Blue 
b) Colourless 
c) Dirty green 
d) Reddish Brown 
1 
3 
Mild non-corrosive basic salt is 
a) Ca (OH) 2 
b) NaCl 
c) NaOH 
d) NaHCO 3 
1 
Page 2


1 
 
 
Sample Question Paper 2023-24 
Class X  
Science (Subject Code – 086)  
 
Max. Marks: 80 Time Allowed: 3 hours 
General Instructions: 
i. This question paper consists of 39 questions in 5 sections. 
ii. All questions are compulsory. However, an internal choice is provided in some questions. A student is 
expected to attempt only one of these questions. 
iii. Section A consists of 20 objective type questions carrying 1 mark each. 
iv. Section B consists of 6 Very Short questions carrying 02 marks each. Answers to these questions 
should be in the range of 30 to 50 words. 
v. Section C consists of 7 Short Answer type questions carrying 03 marks each. Answers to these 
questions should be in the range of 50 to 80 words. 
vi. Section D consists of 3 Long Answer type questions carrying 05 marks each. Answer to these 
questions should be in the range of 80 to 120 words. 
vii. Section E consists of 3 source-based/case-based units of assessment of 04 marks each with sub-parts. 
Section-A 
Select and write the most appropriate option out of the four options given for each 
 of the questions 1 - 20. There is no negative mark for incorrect response. 
Q. Nos. Questions Marks 
1 
 
Identify the product which represents the solid state in the above reaction. 
a) Barium chloride 
b) Barium sulphate 
c) Sodium chloride 
d) Sodium sulphate 
1 
2 
The colour of the solution observed after 30 minutes of placing zinc metal to copper 
sulphate solution is 
a) Blue 
b) Colourless 
c) Dirty green 
d) Reddish Brown 
1 
3 
Mild non-corrosive basic salt is 
a) Ca (OH) 2 
b) NaCl 
c) NaOH 
d) NaHCO 3 
1 
2 
 
4 
On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colourless gas is 
produced when a burning match stick is brought near it. Which of the following correctly 
represents metal ‘X’?  
a) Sodium  
b) Sulphur  
c) Copper  
d) Silver  
1 
5 
Which one of the following correctly represents Sodium oxide?  
 
1 
6 
An element with atomic number_____ will form a basic oxide. 
a) 7 (2,5) 
b) 17  (2,8,7) 
c) 14  (2,8,4) 
d) 11  (2,8,1) 
1 
7 
An element ‘M' has 50% of the electrons filled in the 3
rd
 shell as in the 2nd shell.  The 
atomic number of ‘M’ is: 
a) 10 
b) 12 
c) 14 
d) 18 
1 
8 
Generally food is broken and absorbed within the body of organisms. In which of the 
following organisms is it done outside the body? 
a) Amoeba 
b) Mushroom 
c) Paramoecium  
d) Lice 
1 
9 
Receptors are usually located in sense organs. Gustatory receptors are present in 
a) tongue 
b) nose 
c) eye  
d) ear 
1 
10 
A farmer wants to grow banana plants genetically similar enough to the plants  already 
available in his field. Which one of the following methods would you suggest for this 
purpose? 
a) Regeneration 
b) Budding  
c) Vegetative propagation 
d) Sexual reproduction 
1 
Page 3


1 
 
 
Sample Question Paper 2023-24 
Class X  
Science (Subject Code – 086)  
 
Max. Marks: 80 Time Allowed: 3 hours 
General Instructions: 
i. This question paper consists of 39 questions in 5 sections. 
ii. All questions are compulsory. However, an internal choice is provided in some questions. A student is 
expected to attempt only one of these questions. 
iii. Section A consists of 20 objective type questions carrying 1 mark each. 
iv. Section B consists of 6 Very Short questions carrying 02 marks each. Answers to these questions 
should be in the range of 30 to 50 words. 
v. Section C consists of 7 Short Answer type questions carrying 03 marks each. Answers to these 
questions should be in the range of 50 to 80 words. 
vi. Section D consists of 3 Long Answer type questions carrying 05 marks each. Answer to these 
questions should be in the range of 80 to 120 words. 
vii. Section E consists of 3 source-based/case-based units of assessment of 04 marks each with sub-parts. 
Section-A 
Select and write the most appropriate option out of the four options given for each 
 of the questions 1 - 20. There is no negative mark for incorrect response. 
Q. Nos. Questions Marks 
1 
 
Identify the product which represents the solid state in the above reaction. 
a) Barium chloride 
b) Barium sulphate 
c) Sodium chloride 
d) Sodium sulphate 
1 
2 
The colour of the solution observed after 30 minutes of placing zinc metal to copper 
sulphate solution is 
a) Blue 
b) Colourless 
c) Dirty green 
d) Reddish Brown 
1 
3 
Mild non-corrosive basic salt is 
a) Ca (OH) 2 
b) NaCl 
c) NaOH 
d) NaHCO 3 
1 
2 
 
4 
On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colourless gas is 
produced when a burning match stick is brought near it. Which of the following correctly 
represents metal ‘X’?  
a) Sodium  
b) Sulphur  
c) Copper  
d) Silver  
1 
5 
Which one of the following correctly represents Sodium oxide?  
 
1 
6 
An element with atomic number_____ will form a basic oxide. 
a) 7 (2,5) 
b) 17  (2,8,7) 
c) 14  (2,8,4) 
d) 11  (2,8,1) 
1 
7 
An element ‘M' has 50% of the electrons filled in the 3
rd
 shell as in the 2nd shell.  The 
atomic number of ‘M’ is: 
a) 10 
b) 12 
c) 14 
d) 18 
1 
8 
Generally food is broken and absorbed within the body of organisms. In which of the 
following organisms is it done outside the body? 
a) Amoeba 
b) Mushroom 
c) Paramoecium  
d) Lice 
1 
9 
Receptors are usually located in sense organs. Gustatory receptors are present in 
a) tongue 
b) nose 
c) eye  
d) ear 
1 
10 
A farmer wants to grow banana plants genetically similar enough to the plants  already 
available in his field. Which one of the following methods would you suggest for this 
purpose? 
a) Regeneration 
b) Budding  
c) Vegetative propagation 
d) Sexual reproduction 
1 
3 
 
11 Height of a plant is regulated by: 
a) DNA which is directly influenced by growth hormone. 
b) Genes which regulate the proteins directly. 
c) Growth hormones under the influence of the enzymes coded by a gene. 
d) Growth hormones directly under the influence a gene. 
1 
12 A sportsman, after a long break of his routine exercise, suffered muscular cramps during a 
heavy exercise session. This happened due to:  
a) lack of carbon dioxide and formation of pyruvate. 
b) presence of oxygen and formation of ethanol. 
c) lack of oxygen and formation of lactic acid. 
d) lack of oxygen and formation of carbon dioxide. 
1 
13 
An object is placed in front of a convex mirror. Its image is formed :     
a) at a distance equal to the object distance in front of the mirror.  
b) at twice the distance of the object in front of the mirror. 
c) half the distance of the object in front of the mirror. 
d) behind the mirror and it’s position varies according to the object distance. 
1 
14 
When light enters the atmosphere it strikes on extremely fine particles, which deflect the 
rays of light in all possible directions, This is due to - 
a) reflection of light 
b) atmospheric refraction 
c)  scattering of light 
d)  dispersion of light 
1 
15 
In 1987, an agreement was formulated by the United Nations Environment Programme 
(UNEP) to freeze the production of “X” to prevent depletion of “Y”. “X” and “Y” 
respectively referred here are: 
a) Ozone; CFCs  
b) CFCs; rays  UV  
c) CFCs; Ozone  
d) UV rays; Diatomic oxygen 
1 
16 
Which of the following features relates to biodegradable substances? 
a) Broken down by biological processes 
b) Remain inert  
c) Persist in environment for long time  
d) May harm the ecosystem 
1 
 
Question No. 17 to 20 consist of two statements – Assertion (A) and Reason (R). Answer 
these questions selecting the appropriate option given below:  
a) Both A and R are true, and R is the correct explanation of A.  
b) Both A and R are true, and R is not the correct explanation of A.  
c) A is true but R is false.  
d) A is false but R is true. 
 
17 
Assertion: Rusting of Iron is endothermic in nature. 
Reason:  As the reaction is slow, the release of heat is barely evident.  
1 
18 
Assertion: Probability of survival of an organism produced through sexual reproduction is 
more  than that of organism produced through asexual mode. 
Reason: Variations provide advantages to individuals for survival. 
1 
Page 4


1 
 
 
Sample Question Paper 2023-24 
Class X  
Science (Subject Code – 086)  
 
Max. Marks: 80 Time Allowed: 3 hours 
General Instructions: 
i. This question paper consists of 39 questions in 5 sections. 
ii. All questions are compulsory. However, an internal choice is provided in some questions. A student is 
expected to attempt only one of these questions. 
iii. Section A consists of 20 objective type questions carrying 1 mark each. 
iv. Section B consists of 6 Very Short questions carrying 02 marks each. Answers to these questions 
should be in the range of 30 to 50 words. 
v. Section C consists of 7 Short Answer type questions carrying 03 marks each. Answers to these 
questions should be in the range of 50 to 80 words. 
vi. Section D consists of 3 Long Answer type questions carrying 05 marks each. Answer to these 
questions should be in the range of 80 to 120 words. 
vii. Section E consists of 3 source-based/case-based units of assessment of 04 marks each with sub-parts. 
Section-A 
Select and write the most appropriate option out of the four options given for each 
 of the questions 1 - 20. There is no negative mark for incorrect response. 
Q. Nos. Questions Marks 
1 
 
Identify the product which represents the solid state in the above reaction. 
a) Barium chloride 
b) Barium sulphate 
c) Sodium chloride 
d) Sodium sulphate 
1 
2 
The colour of the solution observed after 30 minutes of placing zinc metal to copper 
sulphate solution is 
a) Blue 
b) Colourless 
c) Dirty green 
d) Reddish Brown 
1 
3 
Mild non-corrosive basic salt is 
a) Ca (OH) 2 
b) NaCl 
c) NaOH 
d) NaHCO 3 
1 
2 
 
4 
On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colourless gas is 
produced when a burning match stick is brought near it. Which of the following correctly 
represents metal ‘X’?  
a) Sodium  
b) Sulphur  
c) Copper  
d) Silver  
1 
5 
Which one of the following correctly represents Sodium oxide?  
 
1 
6 
An element with atomic number_____ will form a basic oxide. 
a) 7 (2,5) 
b) 17  (2,8,7) 
c) 14  (2,8,4) 
d) 11  (2,8,1) 
1 
7 
An element ‘M' has 50% of the electrons filled in the 3
rd
 shell as in the 2nd shell.  The 
atomic number of ‘M’ is: 
a) 10 
b) 12 
c) 14 
d) 18 
1 
8 
Generally food is broken and absorbed within the body of organisms. In which of the 
following organisms is it done outside the body? 
a) Amoeba 
b) Mushroom 
c) Paramoecium  
d) Lice 
1 
9 
Receptors are usually located in sense organs. Gustatory receptors are present in 
a) tongue 
b) nose 
c) eye  
d) ear 
1 
10 
A farmer wants to grow banana plants genetically similar enough to the plants  already 
available in his field. Which one of the following methods would you suggest for this 
purpose? 
a) Regeneration 
b) Budding  
c) Vegetative propagation 
d) Sexual reproduction 
1 
3 
 
11 Height of a plant is regulated by: 
a) DNA which is directly influenced by growth hormone. 
b) Genes which regulate the proteins directly. 
c) Growth hormones under the influence of the enzymes coded by a gene. 
d) Growth hormones directly under the influence a gene. 
1 
12 A sportsman, after a long break of his routine exercise, suffered muscular cramps during a 
heavy exercise session. This happened due to:  
a) lack of carbon dioxide and formation of pyruvate. 
b) presence of oxygen and formation of ethanol. 
c) lack of oxygen and formation of lactic acid. 
d) lack of oxygen and formation of carbon dioxide. 
1 
13 
An object is placed in front of a convex mirror. Its image is formed :     
a) at a distance equal to the object distance in front of the mirror.  
b) at twice the distance of the object in front of the mirror. 
c) half the distance of the object in front of the mirror. 
d) behind the mirror and it’s position varies according to the object distance. 
1 
14 
When light enters the atmosphere it strikes on extremely fine particles, which deflect the 
rays of light in all possible directions, This is due to - 
a) reflection of light 
b) atmospheric refraction 
c)  scattering of light 
d)  dispersion of light 
1 
15 
In 1987, an agreement was formulated by the United Nations Environment Programme 
(UNEP) to freeze the production of “X” to prevent depletion of “Y”. “X” and “Y” 
respectively referred here are: 
a) Ozone; CFCs  
b) CFCs; rays  UV  
c) CFCs; Ozone  
d) UV rays; Diatomic oxygen 
1 
16 
Which of the following features relates to biodegradable substances? 
a) Broken down by biological processes 
b) Remain inert  
c) Persist in environment for long time  
d) May harm the ecosystem 
1 
 
Question No. 17 to 20 consist of two statements – Assertion (A) and Reason (R). Answer 
these questions selecting the appropriate option given below:  
a) Both A and R are true, and R is the correct explanation of A.  
b) Both A and R are true, and R is not the correct explanation of A.  
c) A is true but R is false.  
d) A is false but R is true. 
 
17 
Assertion: Rusting of Iron is endothermic in nature. 
Reason:  As the reaction is slow, the release of heat is barely evident.  
1 
18 
Assertion: Probability of survival of an organism produced through sexual reproduction is 
more  than that of organism produced through asexual mode. 
Reason: Variations provide advantages to individuals for survival. 
1 
4 
 
19 
Assertion : A compass needle is placed near a current carrying wire. The deflection of the 
compass needle decreases when the magnitude of the current in the wire is increased. 
Reason : The strength of a magnetic field at a point near the conductor increases on 
increasing the current. 
1 
20 
 Assertion: Biodegradable substances result in the formation of compost and natural 
replenishment.   
Reason: It is due to breakdown of complex inorganic substances into simple organic 
substances.  
1 
Section-B 
Question No. 21 to 26 are very short answer questions 
21 
Dil. HCl is added to Zn granules.” How will you prove that chemical change has taken place 
here?  Support your response with two arguments. 
2 
22 
State the post-fertilisation changes that lead to fruit formation in plants. 
2 
23 
What is the purpose of making urine in the human body? Name the organs that stores and 
releases the urine. 
OR 
Why do arteries have thick and elastic walls whereas veins have valves? 
2 
24 
The refractive indices of three media are given below:  
Medium Refractive Index 
A 1.6 
B 1.8 
C 1.5 
A ray of light is travelling from A to B and another ray is travelling from B to C.  
(a) In which of the two cases the refracted ray bends towards the normal?  
(b) In which case does the speed of light increase in the second medium?  
Give reasons for your answer. 
2 
25 
A piece of wire of resistance R is cut into three equal parts. These parts are then connected 
in parallel. If the equivalent resistance of this parallel combination is R 1, what is the value 
of the ratio R 1 : R? 
OR 
Refer to the image below and state how the magnetic field pattern indicates regions where 
the magnetic field is stronger outside the magnet? What happens to the magnetic field 
when the current in the circuit is reversed? 
 
2 
Page 5


1 
 
 
Sample Question Paper 2023-24 
Class X  
Science (Subject Code – 086)  
 
Max. Marks: 80 Time Allowed: 3 hours 
General Instructions: 
i. This question paper consists of 39 questions in 5 sections. 
ii. All questions are compulsory. However, an internal choice is provided in some questions. A student is 
expected to attempt only one of these questions. 
iii. Section A consists of 20 objective type questions carrying 1 mark each. 
iv. Section B consists of 6 Very Short questions carrying 02 marks each. Answers to these questions 
should be in the range of 30 to 50 words. 
v. Section C consists of 7 Short Answer type questions carrying 03 marks each. Answers to these 
questions should be in the range of 50 to 80 words. 
vi. Section D consists of 3 Long Answer type questions carrying 05 marks each. Answer to these 
questions should be in the range of 80 to 120 words. 
vii. Section E consists of 3 source-based/case-based units of assessment of 04 marks each with sub-parts. 
Section-A 
Select and write the most appropriate option out of the four options given for each 
 of the questions 1 - 20. There is no negative mark for incorrect response. 
Q. Nos. Questions Marks 
1 
 
Identify the product which represents the solid state in the above reaction. 
a) Barium chloride 
b) Barium sulphate 
c) Sodium chloride 
d) Sodium sulphate 
1 
2 
The colour of the solution observed after 30 minutes of placing zinc metal to copper 
sulphate solution is 
a) Blue 
b) Colourless 
c) Dirty green 
d) Reddish Brown 
1 
3 
Mild non-corrosive basic salt is 
a) Ca (OH) 2 
b) NaCl 
c) NaOH 
d) NaHCO 3 
1 
2 
 
4 
On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colourless gas is 
produced when a burning match stick is brought near it. Which of the following correctly 
represents metal ‘X’?  
a) Sodium  
b) Sulphur  
c) Copper  
d) Silver  
1 
5 
Which one of the following correctly represents Sodium oxide?  
 
1 
6 
An element with atomic number_____ will form a basic oxide. 
a) 7 (2,5) 
b) 17  (2,8,7) 
c) 14  (2,8,4) 
d) 11  (2,8,1) 
1 
7 
An element ‘M' has 50% of the electrons filled in the 3
rd
 shell as in the 2nd shell.  The 
atomic number of ‘M’ is: 
a) 10 
b) 12 
c) 14 
d) 18 
1 
8 
Generally food is broken and absorbed within the body of organisms. In which of the 
following organisms is it done outside the body? 
a) Amoeba 
b) Mushroom 
c) Paramoecium  
d) Lice 
1 
9 
Receptors are usually located in sense organs. Gustatory receptors are present in 
a) tongue 
b) nose 
c) eye  
d) ear 
1 
10 
A farmer wants to grow banana plants genetically similar enough to the plants  already 
available in his field. Which one of the following methods would you suggest for this 
purpose? 
a) Regeneration 
b) Budding  
c) Vegetative propagation 
d) Sexual reproduction 
1 
3 
 
11 Height of a plant is regulated by: 
a) DNA which is directly influenced by growth hormone. 
b) Genes which regulate the proteins directly. 
c) Growth hormones under the influence of the enzymes coded by a gene. 
d) Growth hormones directly under the influence a gene. 
1 
12 A sportsman, after a long break of his routine exercise, suffered muscular cramps during a 
heavy exercise session. This happened due to:  
a) lack of carbon dioxide and formation of pyruvate. 
b) presence of oxygen and formation of ethanol. 
c) lack of oxygen and formation of lactic acid. 
d) lack of oxygen and formation of carbon dioxide. 
1 
13 
An object is placed in front of a convex mirror. Its image is formed :     
a) at a distance equal to the object distance in front of the mirror.  
b) at twice the distance of the object in front of the mirror. 
c) half the distance of the object in front of the mirror. 
d) behind the mirror and it’s position varies according to the object distance. 
1 
14 
When light enters the atmosphere it strikes on extremely fine particles, which deflect the 
rays of light in all possible directions, This is due to - 
a) reflection of light 
b) atmospheric refraction 
c)  scattering of light 
d)  dispersion of light 
1 
15 
In 1987, an agreement was formulated by the United Nations Environment Programme 
(UNEP) to freeze the production of “X” to prevent depletion of “Y”. “X” and “Y” 
respectively referred here are: 
a) Ozone; CFCs  
b) CFCs; rays  UV  
c) CFCs; Ozone  
d) UV rays; Diatomic oxygen 
1 
16 
Which of the following features relates to biodegradable substances? 
a) Broken down by biological processes 
b) Remain inert  
c) Persist in environment for long time  
d) May harm the ecosystem 
1 
 
Question No. 17 to 20 consist of two statements – Assertion (A) and Reason (R). Answer 
these questions selecting the appropriate option given below:  
a) Both A and R are true, and R is the correct explanation of A.  
b) Both A and R are true, and R is not the correct explanation of A.  
c) A is true but R is false.  
d) A is false but R is true. 
 
17 
Assertion: Rusting of Iron is endothermic in nature. 
Reason:  As the reaction is slow, the release of heat is barely evident.  
1 
18 
Assertion: Probability of survival of an organism produced through sexual reproduction is 
more  than that of organism produced through asexual mode. 
Reason: Variations provide advantages to individuals for survival. 
1 
4 
 
19 
Assertion : A compass needle is placed near a current carrying wire. The deflection of the 
compass needle decreases when the magnitude of the current in the wire is increased. 
Reason : The strength of a magnetic field at a point near the conductor increases on 
increasing the current. 
1 
20 
 Assertion: Biodegradable substances result in the formation of compost and natural 
replenishment.   
Reason: It is due to breakdown of complex inorganic substances into simple organic 
substances.  
1 
Section-B 
Question No. 21 to 26 are very short answer questions 
21 
Dil. HCl is added to Zn granules.” How will you prove that chemical change has taken place 
here?  Support your response with two arguments. 
2 
22 
State the post-fertilisation changes that lead to fruit formation in plants. 
2 
23 
What is the purpose of making urine in the human body? Name the organs that stores and 
releases the urine. 
OR 
Why do arteries have thick and elastic walls whereas veins have valves? 
2 
24 
The refractive indices of three media are given below:  
Medium Refractive Index 
A 1.6 
B 1.8 
C 1.5 
A ray of light is travelling from A to B and another ray is travelling from B to C.  
(a) In which of the two cases the refracted ray bends towards the normal?  
(b) In which case does the speed of light increase in the second medium?  
Give reasons for your answer. 
2 
25 
A piece of wire of resistance R is cut into three equal parts. These parts are then connected 
in parallel. If the equivalent resistance of this parallel combination is R 1, what is the value 
of the ratio R 1 : R? 
OR 
Refer to the image below and state how the magnetic field pattern indicates regions where 
the magnetic field is stronger outside the magnet? What happens to the magnetic field 
when the current in the circuit is reversed? 
 
2 
5 
 
26 
Study the food chain given below and answer the questions that follow: 
 
a) If the amount of energy available at the third trophic level is 100 joules, then how 
much energy will be available at the producer level? Justify your answer. 
b) Is it possible to have 2 more trophic levels in this food chain just before the fourth 
trophic level? Justify your answer. 
2 
Section-C 
Question No. 27 to 33 are short answer questions 
27 
The given reaction shows one of the processes to extract the metals like Iron and 
Manganese. 
MnO2 (s) + Al(s) ? Mn(l) + Al2O3(s) + Heat 
a) Give reason why the  above reaction is known as a thermite reaction.   
b) Identify the substance oxidised and reduced in the above reaction. 
c) Give a reason why Aluminium is  preferably used in thermite reactions. 
3 
28 
An element ‘M’ with electronic configuration 2 8 3 combines separately with Cl
-
, SO4
-2
 
anions.  Write the chemical formulae of the compounds formed. Predict with the suitable 
reason the nature of the bond formed by element ‘M’ in general. How will the electrical 
conductivity of the compounds formed vary with respect to ‘M’? 
OR 
A reddish-brown metal ‘X’, when heated in air, gives a black compound ‘Y’, which when 
heated in presence of H2 gas gives ‘X’ back.   ‘X’ is refined by the process of electrolysis; 
this refined form of ‘X’ is used in electrical wiring. 
Identify ‘X’ and ‘Y’. Draw a well-labeled diagram to represent the process of refining ‘X’. 
3 
29 
We are advised to take iodised salt in our diet by doctors. Justify it's importance in our 
body.  
3 
30 
What is the probability of a girl or a boy being born in a family? Justify your answer. 
3 
31 
(i) Explain why the refractive index of any material with respect to air is always greater 1. 
(ii) In the figure below a light ray travels from air into the semi-circular plastic block. Give 
a reason why the ray does not deviate at the semi-circular boundary of the plastic 
block. 
 
(iii) Complete the ray diagram of the above scenario when the light ray comes out of the 
plastic block from the top flat end.  
1+1+1 
32 
(i) State the law that explains the heating effect of current with respect to the measurable 
properties in an electrical circuit. 
(ii) List the factors on which the resistance of a conductor depends. 
2+1